Automotive passenger restraint and protection apparatus

ABSTRACT

An automotive passenger restraint and protection apparatus for an automotive vehicle has a seatbelt and operates to restrain an occupant of the automotive vehicle by the seatbelt to protect the occupant. An electric retractor has a DC motor for retracting and protracting the seatbelt. An MPU applies voltage having a predetermined waveform to the DC motor, and then detects a waveform of current flowing to the DC motor. The MPU carries out fault diagnosis of the DC motor, based upon the detected waveform of current when the voltage having the predetermined waveform is applied to the DC motor. Thus, accurate fault diagnosis of the apparatus can be achieved.

[0001] This is a Division of application Ser. No. 10/385,811 filed Mar.11, 2003, which is a Division of application Ser. No. 09/862,052 filedMay 21, 2001, now U.S. Pat. No. 6,561,299 issued May 13, 2003, which isa Division of application Ser. No. 09/207,911 filed Dec. 9, 1998, nowU.S. Pat. No. 6,257,363 issued Jul. 10, 2001.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to an automotive passenger restraint andprotection apparatus for automotive vehicles such as automobiles, whichuses an electric retracting and protracting a seatbelt for an occupant(driver or passenger).

[0004] 2. Prior Art

[0005] An automotive passenger restraint and protection apparatus isconventionally known, which has an electric retractor which protractsand retracts a seatbelt. The electric retractor has driving meansformed, e.g. of an electric motor (hereinafter referred to as “motor” or“DC motor”) for driving the electric retractor.

[0006] In the conventional automotive passenger restraint and protectionapparatus of this type, fault diagnosis of the apparatus is carried outby pulling out or releasing a seatbelt by the occupant to ascertainwhether the seatbelt can be actually protracted or retracted.

[0007] The above manner of fault diagnosis is unable to accuratelydetect faults in a DC motor for driving the electric retractor and itsperipheral parts.

[0008] There have been proposed many other fault diagnosis methods forautomotive passenger restraint and protection apparatuses.

[0009] One of these conventional methods is a method of detectingtemperature in the vicinity of the motor by a temperature sensor ordetecting current flowing to the motor by a current detecting circuit,and determining by an MPU (Micro Processing Unit) of the apparatus thatthere is is a fault in the apparatus when the detected temperature valueor current value continuously exceeds a predetermined value over apredetermined time period. Upon determination that there is a fault inthe apparatus, the MPU causes the motor to be stopped to prevent firingof the motor.

[0010] According to the above fault diagnosis method, however, if anabnormality occurs in a power transmission mechanism which transmits adriving force from the motor to a reel shaft which has the seatbeltwound thereon such that the power transmission cannot transmit thedriving force and accordingly the motor runs idle, the temperature inthe vicinity of the motor rises and the current flowing to the motorincreases but not to such a degree that the MPU can determine that thereis a fault or abnormality. Consequently, such a kind of abnormalitycannot be detected by the conventional fault diagnosis method.

[0011] Further, if no countermeasure is taken to eliminate such anabnormality of the power transmission mechanism, the motor may have ashortened effective life.

[0012] On the other hand, if the motor for driving the electricretractor is continuously operated for a long time, the temperature ofthe motor rises and can exceed the withstand temperature so that themotor can become faulty.

[0013] The conventional automotive passenger restraint and protectionapparatus, however, is not provided with a function of preventing such akind of fault.

[0014] The conventional automotive passenger restraint and protectionapparatuses include a type which has a function of carrying out aseatbelt slackening operation for giving a predetermined amount oflooseness to the seatbelt if seatbelt attaching detecting means detectsthat the seatbelt has shifted from a state disconnected from theoccupant to a state attached to the occupant, and carrying out aseatbelt storing operation for storing the seatbelt into a retractedposition if the seatbelt attaching detecting means detects that theseatbelt has shifted from the attached state to the disconnected state.

[0015] Further, the conventional automotive passenger restraint andprotection apparatuses include a type which has a function of carryingout a seatbelt slackening operation of retracting the seatbelt to aretraction limit position (hereinafter merely referred to as “limit”unless otherwise specified) if the seatbelt is protracted by theoccupant in attaching the seatbelt to his body, and then protracting theseatbelt so as to give a predetermined amount of looseness to theseatbelt.

[0016] If, however, the seatbelt attaching detecting means becomesfaulty such that it always determines that the seatbelt is disconnectedfrom the occupant even when the seatbelt is attached to the occupant,the seatbelt slackening operation cannot be performed even when theseatbelt has been attached to the occupant, whereby a predeterminedamount of looseness cannot be given to the seatbelt, failing toproviding a comfortable seatbelt wearing feeling for the occupant.Further, even if the seatbelt has shifted to the disconnected state fromthe attached state with the seatbelt attaching detecting means beingfaulty, the seatbelt storing operation cannot be performed, so that theseatbelt is held in the disconnected or protracted state.

[0017] Conversely, if the seatbelt attaching detecting means becomesfaulty such that it always determines that the seatbelt is attached tothe occupant even when the seatbelt is disconnected from the occupant,the seatbelt slackening operation can be carried out while the seatbeltis in the stored state, failing to keep the seatbelt in a proper storedstate. Further, in this state, if the seatbelt is attached to theoccupant, body, a determination is made that the seatbelt has beenprotracted from a state attached to the occupant, so that the seatbeltslackening operation is carried out. However, if then the seatbelt isdisconnected from the occupant, a determination is made that theseatbelt is attached to the occupant, so that the seatbelt storingoperation cannot be performed, whereby the seatbelt is held in theprotracted state.

[0018] Moreover, in the above type of automotive passenger restraint andprotection apparatus, the seatbelt is always given a fixed amount oflooseness irrespective of whether there is a fear of collision of theautomotive vehicle. Therefore, the above function is not perfect toproperly protect the occupant.

[0019] Further, in the conventional automotive passenger restraint andprotection apparatus, the power consumption of the MPU is notcontemplated. As a result, for example, the MPU operates so as toexhibit its full function even in the case where the full function ofthe MPU need not be exhibited.

[0020] On the other hand, an automotive passenger restraint andprotection apparatus is conventionally known, which is provided withdriving/traveling state detecting means which detects a collision dangerstate and a collision unavoidable state of the automotive vehicle, and adozing state of the driver.

[0021] According to this type of automotive passenger restraint andprotection apparatus, if the driving/traveling state detecting meansdetects the collision danger state of the automotive vehicle or thedozing state of the driver, protraction and retraction of the seatbeltare alternately carried out at irregular time intervals so as to alertthe occupant or driver to the danger. Further, if the collisionunavoidable state of the automotive vehicle is detected, the seatbelt isretracted with a predetermined magnitude of retracting force so as toproperly protect the occupant upon a collision of the automotivevehicle.

[0022] In the conventional automotive passenger restraint and protectionapparatus, however, once the ignition switch of the automotive vehicleis turned on, electric power is supplied from the power supply all thetime thereafter, so that the electric power is consumed even when thedriving/traveling state detecting means need not be operated.

[0023] Further, the electric retractor is constructed such that oncedisconnection of the seatbelt from the occupant is detected, it retractsthe seatbelt into its fully retracted position.

[0024] Therefore, if the occupant once releases a tongue of the seatbeltfrom a buckle secured to the seat into a disconnected state andimmediately then attaches the tongue of the seat to the buckle, he hasto manually protract the seatbelt against the retracting force of theelectric retractor. Thus, a large force is required for protracting theseatbelt, and therefore a weak occupant who has degraded physicalability such as an advanced-age occupant takes long to mount theseatbelt onto his body.

[0025] Further, an automotive passenger restraint and protectionapparatus has been proposed, e.g. by Japanese Laid-Open PatentPublication (Kokai) No. 9-175327, which includes an electric retractor,and collision danger predicting means, wherein the electric retractoroperates in response to a signal indicative of collision danger from thecollision danger predicting means, to cause vibration by alternatelyapplying and releasing pressure to and from the occupant through theseatbelt. This vibration is continued until a signal indicative of acollision being unavoidable is received from the collision dangerpredicting means or the signal indicative of collision danger ceases tobe received.

[0026] The proposed automotive passenger restraint and protectionapparatus are, however, required to be still improved in the followingpoints. That is, the collision danger predicting means merely predictsor foresees a future phenomenon but cannot perfectly predict a futurephenomenon. Therefore, according to the proposed construction that stopsvibration by alternate application and release of pressure upon stoppingof receipt of the collision danger signal, the collision danger signalis not received even when there is still a possibility that the vehicleencounters a collision, so that the vibration is stopped. Thus,sufficient warning cannot be given to the occupant.

[0027] Further, in the conventional automotive passenger restraint andprotection apparatus, in the case where when the seatbelt is in a statedisconnected from the occupant, when the seat is protracted by theoccupant, the time period after the protraction of the seatbelt by theoccupant is stopped and before retraction of the seat is started by theelectric retractor is almost constant irrespective of the speed of theprotraction of the seatbelt by the occupant. More specifically, theoccupant with the seatbelt not attached to his body protracts theseatbelt in order to mount the seatbelt onto his body, and thereafterstops protracting the seatbelt since he cannot easily soon engage thetongue of the seatbelt with the buckle and hence takes time to mount theseatbelt onto his body. The time period after the stoppage ofprotraction of the seatbelt by the occupant and before retraction of theseatbelt by the electric retractor is started is set to a predeterminedfixed time period which corresponds to the expected time that theoccupant should take by trying to engage the seatbelt with the buckle.

[0028] However, if the occupant protracts the seatbelt without theintention of mounting the seatbelt onto his body and then gets off theautomotive vehicle and closes the door, retraction of the seatbelt bythe electric retractor is not carried out over the set predeterminedtime period. As a result, the protracted seatbelt can be caught in thedoor when the occupant closes the door. On the other hand, in the casewhere the occupant takes longer time than expected to mount the seatbeltonto his body, retraction of the seatbelt by the electric retractor canstart before the occupant completes the mounting. Then, the occupanttakes long to mount the seatbelt onto his body due to the retractingforce of the electric retractor.

[0029] The time period after the seatbelt is protracted by the occupantand before he closes the door after getting off the automotive vehiclevaries depending upon the occupant's physical ability. Generallyspeaking, in the case of an occupant having a high physical ability, thetime the occupant takes to get off the vehicle is short and the timeperiod after the occupant protracts and before he closes the door isshort, whereas in the case of an occupant having a low physical ability,the time the occupant takes to get off the vehicle is long and the timeperiod after the occupant protracts and before he closes the door islong. Further, generally speaking, the seatbelt protracting speed of anoccupant of a high physical ability is high, whereas that of an occupantof a low physical ability is low. Accordingly, generally, the timeperiod after stoppage of protraction of the seatbelt by the occupant andbefore completion of mounting of the seatbelt onto his body isrelatively short in the case of an occupant of a high physical ability,and relatively long in the case of an occupant of a low physicalability.

[0030] In the conventional automotive passenger restraint and protectionapparatus, however, the time period after the stoppage of protraction ofthe seatbelt by the occupant and before the start of retraction of theseat by the electric retractor is set to an almost constant valueirrespective of the physical ability of the occupant. Therefore, if theset time period is a relatively long time period corresponding to anoccupant of a low physical ability, when an occupant of a high physicalability gets off the vehicle and closes the door in a relatively shorttime, the seatbelt can be caught in the door, while if the set timeperiod is a relatively short time period corresponding to an occupant ofa high physical ability, when an occupant of a low physical abilitymounts the seatbelt onto his body, the seatbelt starts to be retractedby the electric retractor before he finishes mounting the seatbelt ontohis body, thus impeding the occupant's mounting motion.

[0031] Further, in the conventional automotive passenger restraint andprotection apparatus, supply voltage to the electric retractor issupplied from a battery provided in the automotive vehicle all the time,as known from Japanese Laid-Open Utility Model publication (Kokai) No.61-134464. Further, in the apparatus according to this publication, theseatbelt is not retracted after disconnection of the seatbelt from theoccupant.

[0032] According to this conventional automotive passenger restraint andprotection apparatus, however, since the supply voltage to the electricretractor is supplied from the batter all the time, the battery isconsumed even when the supply voltage need not be supplied to theelectric retractor, resulting in early deterioration of the battery.

[0033] Further, since the seatbelt is not retracted after disconnectionof the seatbelt from the occupant, there is a possibility that thetongue of the seatbelt can be caught in the door.

SUMMARY OF THE INVENTION

[0034] It is a first object of the invention to provide an automotivepassenger restraint and protection apparatus which is capable ofachieving accurate fault diagnosis of the apparatus.

[0035] A second object of the invention is to provide an automotivepassenger restraint and protection apparatus which is capable ofperforming accurate fault diagnosis of the apparatus and giving warningupon detection of a fault to alert the occupant to the fault.

[0036] A third object of the invention is to provide an automotivepassenger restraint and protection apparatus which is capable ofpreventing driving means for protracting and retracting the seatbeltfrom becoming faulty.

[0037] A fourth object of the invention is to provide an automotivepassenger restraint and protection apparatus which is capable ofproviding a comfortable seatbelt attaching feeling and preventing theseatbelt from being damaged even when attaching or disconnection of theseatbelt to or from the occupant cannot be accurately detected due to afault.

[0038] A fifth object of the invention is to provide an automotivepassenger restraint and protection apparatus which is capable ofchanging the operative state of control means of the apparatus accordingto the expected ability thereof to thereby reduce the power consumption.

[0039] A sixth an automotive passenger restraint and protectionapparatus which is capable of supplying electric power todriving/traveling state detecting means only when the driving/travelingstate detecting means needs to be operated, to thereby reduce the powerconsumption.

[0040] A seventh object of the invention is to provide an automotivepassenger restraint and protection apparatus which is capable offacilitating mounting of the seatbelt onto the occupant even when theoccupant has a low physical ability to thereby properly protect theoccupant.

[0041] An eighth object of the invention is to provide an automotivepassenger restraint and protection apparatus which is capable ofpreventing the seatbelt from being caught in the door of the automotivevehicle.

[0042] A ninth object of the invention is to provide an automotivepassenger restraint and protection apparatus which is capable ofcontinuing vibration by alternate application and release of pressure toand from the occupant as long as it is expected that the automotivevehicle runs into danger even after a collision danger signal ceases tobe received, to thereby fully alert the occupant to the danger.

[0043] A tenth object of the invention is to provide an automotivepassenger restraint and protection apparatus which is capable ofaccurately determining the degree of danger of collision of theautomotive vehicle.

[0044] An eleventh object of the invention is to provide an automotivepassenger restraint and protection apparatus which is capable ofproperly protecting the occupant in a manner dependent upon the degreeof danger of collision of the automotive vehicle.

[0045] A twelfth object of the invention is to provide an automotivepassenger restraint and protection apparatus which is capable ofpreventing deterioration of the power supply.

[0046] To attain the first object, according to a first aspect of theinvention, there is provided an automotive passenger restraint andprotection apparatus for an automotive vehicle, having a seatbelt, forrestraining an occupant of the automotive vehicle by the seatbelt toprotect the occupant, comprising an electric retractor having drivingmeans for retracting and protracting the seatbelt, voltage waveformapplying means for applying voltage having a predetermined waveform tothe driving means, current waveform detecting means for detecting awaveform of current flowing to the driving means, and fault diagnosismeans for carrying out fault diagnosis of the driving means, based uponthe waveform of current detected by the current waveform detecting meanswhen the voltage waveform applying means applies the voltage having thepredetermined waveform to the driving means.

[0047] According to the first aspect, fault diagnosis of the drivingmeans is carried out based upon a waveform of current detected by thecurrent waveform detecting means when the voltage waveform applyingmeans applies voltage having a predetermined waveform to the drivingmeans. As a result, it is possible to determine whether the drivingmeans is functioning normally or abnormally, in an electric manner,thereby achieving accurate fault diagnosis of the apparatus.

[0048] To attain the first object, according to a second aspect of theinvention, there is provided an automotive passenger restraint andprotection apparatus for an automotive vehicle, having a seatbelt, forrestraining an occupant of the automotive vehicle by the seatbelt toprotect the occupant, comprising an electric retractor having drivingmeans for retracting and protracting the seatbelt, a load having loadcharacteristics equivalent to electrical characteristics of the drivingmeans, voltage waveform applying means for selectively selectivelyapplying voltage having a predetermined waveform to the driving meansand the load, current waveform detecting means for detecting a waveformof current flowing to the driving means or to the load, and faultdiagnosis means for carrying out fault diagnosis of the driving means,based upon the waveform of current detected by the current waveformdetecting means when the voltage waveform applying means applies thevoltage having the predetermined waveform to the driving means and thewaveform of current detected by the current waveform detecting meanswhen the voltage waveform applying means applies the voltage having thepredetermined waveform to the load.

[0049] According to the second aspect, fault diagnosis of the drivingmeans is carried out based upon a waveform of current detected by thecurrent waveform detecting means when the voltage waveform applyingmeans applies voltage having a predetermined waveform to the drivingmeans and a waveform of current detected by the current waveformdetecting means when the voltage waveform applying means applies thevoltage having the predetermined waveform to the load. As a result, itis possible to determine whether the driving means is functioningnormally or abnormally, in an electric manner, thereby achievingaccurate fault diagnosis of the apparatus.

[0050] To attain the second object, according to a third aspect of theinvention, there is provided an automotive passenger restraint andprotection apparatus for an automotive vehicle, having a seatbelt, forrestraining an occupant of the automotive vehicle by the seatbelt toprotect the occupant, comprising an electric retractor having drivingmeans for retracting and protracting the seatbelt, warning means forgiving warning upon occurrent of a fault of the driving means, controlmeans for controlling the driving means and the warning means, andterminal voltage measuring means for measuring terminal voltage acrossthe driving means, wherein the control means stops operation of thedriving means and causes the warning means to give warning when thedriving means has continued to operate over a predetermined time periodwhile the terminal voltage measured by the terminal voltage measuringmeans falls within a range between a first predetermined value and asecond predetermined value.

[0051] According to the third aspect, the control means stops operationof the driving means and causes the warning means to give warning whenthe driving means has continued to operate over a predetermined timeperiod while the terminal voltage measured by the terminal voltagemeasuring means falls within a range between a first predetermined valueand a second predetermined value. As a result, it is possible to performaccurate fault diagnosis of the apparatus and give warning upondetection of a fault to alert the occupant to the fault.

[0052] Preferably, the voltage range between the first predeterminedvalue and the second predetermined is a range that can be assumed whenthe driving means runs idle while it is functioning normally.

[0053] To attain the second object, according to a fourth aspect of theinvention, there is provided an automotive passenger restraint andprotection apparatus for an automotive vehicle, having a seatbelt, forrestraining an occupant of the automotive vehicle by the seatbelt toprotect the occupant, comprising an electric retractor having drivingmeans for retracting and protracting the seatbelt, warning means forgiving warning upon occurrent of a fault of the driving means, controlmeans for controlling the driving means and the warning means, andcurrent detecting means for detecting current flowing to the drivingmeans, wherein the control means stops operation of the driving meansand causes the warning means to give warning when the driving means hascontinued to operate over a predetermined time period while the currentdetected by the current detecting means falls within a range between afirst predetermined value and a second predetermined value.

[0054] According to the fourth aspect, the control means stops operationof the driving means and causes the warning means to give warning whenthe driving means has continued to operate over a predetermined timeperiod while the current detected by the current detecting means fallswithin a range between a first predetermined value and a secondpredetermined value. As a result, it is possible to perform accuratefault diagnosis of the apparatus and give warning upon detection of afault to alert the occupant to the fault.

[0055] Preferably, the current range between the first predeterminedvalue and the second predetermined is a range that can be assumed whenthe driving means runs idle while it is functioning normally.

[0056] To attain the third object, according to a fifth aspect of theinvention, there is provided an automotive passenger restraint andprotection apparatus for an automotive vehicle, having a seatbelt, forrestraining an occupant of the automotive vehicle by the seatbelt toprotect the occupant, comprising an electric retractor having drivingmeans for retracting and protracting the seatbelt, supply voltagesupplying means for supplying supply voltage to the driving means,abnormality detecting means for detecting abnormality of the drivingmeans, and supply voltage decreasing means for decreasing the supplyvoltage supplied to the driving means by the supply voltage supplyingmeans when the abnormality of the driving means is detected by theabnormality detecting means.

[0057] According to the fifth aspect, the supply voltage supplied to thedriving means by the supply voltage supplying means is decreased whenabnormality of the driving means is detected by the abnormalitydetecting means. As a result, excessively high supply voltage is notapplied to the driving means to thereby prevent the driving means frombecoming faulty.

[0058] Preferably, the automotive passenger restraint and protectionapparatus according to the fifth aspect includes current detecting meansfor detecting current flowing to the driving means, and timer means formeasuring a time period during which the current detected by the currentdetecting means exceeds a predetermined value, and wherein theabnormality detecting means detects that the driving means is abnormalwhen the time period measured by the timer means exceeds a predeterminedtime period.

[0059] Also preferably, the automotive passenger restraint andprotection apparatus according to the fifth aspect includes tensiondetecting means for detecting tension of the seatbelt, and timer meansfor measuring a time period during which the tension detected by thetension detecting means exceeds a predetermined value, and wherein theabnormality detecting means detects that the driving means is abnormalwhen the time period measured by the timer means exceeds a predeterminedtime period.

[0060] Also preferably, the automotive passenger restraint andprotection apparatus according to the fifth aspect includes torquedetecting means for detecting rotational torque of the electricretractor, and timer means for measuring a time period during which therotational torque detected by the torque detecting means exceeds apredetermined value, and wherein the abnormality detecting means detectsthat the driving means is abnormal when the time period measured by thetimer means exceeds a predetermined time period.

[0061] Also preferably, the automotive passenger restraint andprotection apparatus according to the fifth aspect includes temperaturedetecting means for detecting temperature in a vicinity of the drivingmeans or temperature of the driving means, and timer means for measuringa time period during which the temperature detected by the temperaturedetecting means exceeds a predetermined value, and wherein theabnormality detecting means detects that the driving means is abnormalwhen the time period measured by the timer means exceeds a predeterminedtime period.

[0062] To attain the fourth object, according to a sixth aspect of theinvention, there is provided an automotive passenger restraint andprotection apparatus for an automotive vehicle, having a seatbelt, forrestraining an occupant of the automotive vehicle by the seatbelt toprotect the occupant, comprising a reel shaft having the seatbelt woundthereon, winding amount detecting means for detecting an amount ofwinding of the seatbelt on the reel shaft, driving means for rotatingthe reel shaft in a direction of retracting the seatbelt and in adirection of protracting the seatbelt, control means for controlling thedriving means, seatbelt attaching detecting means for detecting whetherthe seatbelt is attached to the occupant or disconnected from theoccupant, and fault detecting means for detecting a fault of theseatbelt attaching detecting means, wherein the control means controlsthe driving means according to the amount of winding of the seatbelt onthe reel shaft detected by the winding amount detecting means, when thefault of the seatbelt attaching detecting means is detected by the faultdetecting means.

[0063] According to the sixth aspect, the driving means is controlledaccording to an amount of winding of the seatbelt on the reel shaftdetected by the winding amount detecting means, when a fault of theseatbelt attaching detecting means is detected by the fault detectingmeans. As a result, even when attaching or disconnection of the seatbeltto or from the occupant cannot be accurately detected due to a fault, ifthe amount of winding of the seatbelt detected by the winding amountdetecting means is small, it is judged that the seatbelt is attached tothe occupant, and then the seatbelt is retracted to the retractionlimit, followed by being given a predetermined amount of looseness. Onthe other hand, if the amount of winding of the seatbelt detected by thewinding amount detecting means is large, it is judged that the seatbeltis disconnected from the occupant, and then the seatbelt is stored intoits retracted position. Thus, even when attaching or disconnection ofthe seatbelt to or from the occupant cannot be accurately detected dueto a fault it is possible to provide a comfortable seatbelt attachingfeeling and prevent the seatbelt from being damaged.

[0064] To attain the fifth object, according to a seventh aspect of theinvention, there is provided an automotive passenger restraint andprotection apparatus for an automotive vehicle, having a seatbelt, forrestraining an occupant of the automotive vehicle by the seatbelt toprotect the occupant, comprising an electric retractor having drivingmeans for retracting and protracting the seatbelt, seatbelt attachingdetecting means for detecting attaching of the seatbelt to the occupantor disconnection of the seatbelt from the occupant, and seatbeltprotraction detecting means for detecting protraction of the seatbelt bythe occupant, and control means for controlling the driving means byperforming a plurality of functions, the control means having selectingmeans for selecting a reduced power consumption mode for permitting thecontrol means to perform at least one minimum required function of theplurality of functions so as to save power consumption by the electricretractor, or a normal power consumption mode for permitting the controlmeans to perform all of the plurality of functions so as not to savepower consumption by the electric retractor, wherein the selecting meansselects the reduced power consumption mode when a predetermined timeperiod has elapsed after detection of the disconnection of the seatbeltfrom the occupant by the seatbelt attaching detecting means while thenormal power consumption mode is selected, and selects the normal powerconsumption mode when the protraction of the seatbelt by the occupant isdetected by the seatbelt protraction detecting means or when theattaching of the seatbelt to the occupant is detected by the seatbeltattaching detecting means.

[0065] According to the seventh aspect, the reduced power consumptionmode is selected when a predetermined time period has elapsed afterdetection of disconnection of the seatbelt from the occupant by theseatbelt attaching detecting means while a normal power consumption modeis selected, and the normal power consumption mode is selected whenprotraction of the seatbelt by the occupant is detected by the seatbeltprotraction detecting means or when attaching of the seatbelt to theoccupant is detected by the seatbelt attaching detecting means. Thus,the operative state of the control means can be changed according to theexpected ability thereof. As a result, it is possible to reduce thepower consumption.

[0066] To attain the sixth object, according to an eighth aspect of theinvention, there is provided an automotive passenger restraint andprotection apparatus for an automotive vehicle, having a seatbelt, forrestraining an occupant of the automotive vehicle by the seatbelt toprotect the occupant, comprising an electric retractor having drivingmeans for retracting and protracting the seatbelt, vehicle stoppagedetecting means for detecting stoppage of the automotive vehicle,driving/traveling state detecting means for detecting states of drivingand traveling of the automotive vehicle by the occupant, supply meansfor supplying electric power to the driving/traveling state detectingmeans, and control means for controlling the supply means so as to stopsupply of the power to the driving/traveling state detecting means whenthe stoppage of the automotive vehicle is detected by the vehiclestoppage detecting means.

[0067] According to the eighth aspect, the supply means is controlled soas to stop supply of electric power to the driving/traveling statedetecting means when stoppage of the automotive vehicle is detected bythe vehicle stoppage detecting means. Thus, electric power is suppliedto the driving/traveling state detecting means only when the latterneeds to be operated, to thereby reduce the power consumption.

[0068] Preferably, the vehicle stoppage detecting means comprises atleast one of seatbelt attaching detecting means for detecting whetherthe seatbelt is attached to the occupant, shift position detecting meansfor detecting whether a shift position of a transmission of theautomotive vehicle is in a parking position, and parking brake detectingmeans for detecting whether a parking brake of the automotive vehicle isoperated.

[0069] To attain the seventh object, according to a ninth aspect of theinvention, there is provided an automotive passenger restraint andprotection apparatus for an automotive vehicle, having a seatbelt, forrestraining an occupant of the automotive vehicle by the seatbelt toprotect the occupant, comprising an electric retractor having drivingmeans for retracting and protracting the seatbelt, control means forcontrolling the driving means, seatbelt protraction detecting means fordetecting protraction of the seatbelt by the occupant, and releasedetecting means for detecting release of the seatbelt from a stateattached to the occupant to a state disconnected from the occupant,wherein the control means controls the driving means so as to startretraction of the seatbelt when the release of the seatbelt is detectedby the release detecting means, controls the driving means so as to stopoperation thereof over a predetermined time at least one time after thestart of retraction of the seatbelt and before completion of theretraction, and controls the driving means so as to protract theseatbelt when the protraction is detected by the seatbelt protractiondetecting means within the predetermined time period.

[0070] According to the ninth aspect, the driving means is controlled soas to start retraction of the seatbelt when release of the seatbelt isdetected by the release detecting means, then controlled so as to stopoperation thereof over a predetermined time at least one time after thestart of retraction of the seatbelt and before completion of theretraction, and controlled so as to protract the seatbelt whenprotraction of the seatbelt is detected by the seatbelt protractiondetecting means within the predetermined time period. As a result, theoccupant need not pull out or protract the seatbelt against theretracting force of the driving means, thereby facilitating mounting ofthe seatbelt onto the occupant.

[0071] To attain the eighth object, according to a tenth aspect of theinvention, the control means of the automotive restraint and protectionapparatus according to the ninth aspect controls the driving means so asto retract the seatbelt when the protraction is not detected by theseatbelt protraction detecting means within the predetermined timeperiod. This can avoid that the seatbelt is left in a protracted state,to thereby prevent the seatbelt from being caught in the door.

[0072] To attain the ninth object, according to an eleventh aspect ofthe invention, there is provided an automotive passenger restraint andprotection apparatus for an automotive vehicle, having a seatbelt, forrestraining an occupant of the automotive vehicle by the seatbelt toprotect the occupant, comprising danger degree determining means fordetermining a degree of danger of collision of the automotive vehicle,danger predicting means for predicting a possibility of collision of theautomotive vehicle, from the degree of danger determined by the dangerdegree determining means, collision danger signal generating means forgenerating a collision danger signal when the possibility of collisionis predicted by the danger predicting means, driving means responsive tothe collision danger signal, for carrying out alternate retraction andprotraction of the seatbelt, deceleration detecting means for detectingdeceleration of the automotive vehicle, and seatbelt driving controlmeans for controlling the driving means so as to continue the alternateretraction and protraction of the seatbelt without stopping same afterthe collision danger signal ceases to be generated and until thedeceleration of the automotive vehicle detected by the decelerationdetecting means exceeds a predetermined value.

[0073] According to the eleventh aspect, the driving means is controlledto continue alternate retraction and protraction of the seatbelt withoutstopping same even after the collision danger signal ceases to begenerated, so long as it is expected that the automotive vehicle runsinto danger, to thereby fully alert the occupant to the danger. Thus,the automotive restraint and protection apparatus can be utilized as awarning device.

[0074] To attain the seventh object, according to a twelfth aspect ofthe invention, there is provided an automotive passenger restraint andprotection apparatus for an automotive vehicle, having a seatbelt, forrestraining an occupant of the automotive vehicle by the seatbelt toprotect the occupant, comprising seatbelt attaching state detectingmeans for detecting whether the seatbelt is in a state attached to theoccupant or in a state disconnected from the occupant, seatbeltprotraction detecting means for detecting protraction of the seatbelt bythe occupant, seatbelt protraction stoppage detecting means fordetecting stoppage of protraction of the seatbelt, inhibiting means forinhibiting retraction of the seatbelt over a predetermined time periodafter the stoppage of protraction of the seatbelt is detected by theseatbelt protraction stoppage detecting means after the protraction ofthe seatbelt is detected by the seatbelt protraction detecting meanswhile the seatbelt is detected to be in the state disconnected from theoccupant by the seatbelt attaching state detecting means, protractingspeed detecting means for detecting speed of protraction of theseatbelt, and setting means for setting the predetermined time periodaccording to the speed of protraction of the seatbelt detected by theprotracting speed detecting means.

[0075] According to the twelfth aspect, a predetermined time period overwhich retraction of the seatbelt is inhibited after stoppage ofprotraction of the seatbelt is detected following detection of theprotraction of the seatbelt while the seatbelt is a state disconnectedfrom the occupant, is set according to the speed of protraction of theseatbelt detected by the protracting speed detecting means. As a result,even when an occupant of a high physical ability gets off the vehicleand closes the door in a short time after protracting the seatbelt, itcan be prevented that the seatbelt is caught in the door. On the otherhand, when an occupant of a low physical ability mounts the seatbeltonto his body, it can be prevented that the seatbelt starts to beretracted before he finishes mounting the seatbelt onto his body toimpede his mounding motion, whereby mounting of the seatbelt onto theoccupant is facilitated.

[0076] Preferably, the setting means sets the predetermined time periodto a shorter value as the speed of protraction of the seatbelt detectedby the protracting speed detecting means is higher, and to a longervalue as the detected speed of protraction of the seatbelt is lower.

[0077] To attain the tenth object, according to a thirteenth aspect ofthe invention, there is provided an automotive passenger restraint andprotection apparatus for an automotive vehicle, having a seatbelt, forrestraining an occupant of the automotive vehicle by the seatbelt toprotect the occupant, comprising a motor for retracting and protractingthe seatbelt, seatbelt attaching state detecting means for detectingwhether the seatbelt is in a state attached to the occupant or in astate disconnected from the occupant, danger degree detecting means fordetecting a significant degree of danger of collision of the automotivevehicle, and control means for controlling the motor so as to retractthe seatbelt to a limit thereof and then protract the seatbelt tothereby give a predetermined amount of looseness to the seatbelt,wherein the control means controls the motor so as to give a firstpredetermined amount of looseness to the seatbelt when the significantdegree of danger is not detected by the danger degree detecting meanswhile the seatbelt is detected to be in the state attached to theoccupant, and controls the motor so as to give a second predeterminedamount of looseness to the seatbelt which is smaller than the firstpredetermined amount of looseness when the significant degree of dangeris detected by the danger degree detecting means while the seatbelt isdetected to be in the state attached to the occupant.

[0078] According to the thirteenth aspect, the motor is controlled so asto give a first predetermined amount of looseness to the seatbelt when asignificant degree of danger is not detected by the danger degreedetecting means while the seatbelt is in a state attached to theoccupant, and controlled so as to give a second predetermined amount oflooseness to the seatbelt which is smaller than the first predeterminedamount of looseness when the significant degree of danger is detected bythe danger degree detecting means while the seatbelt is in the stateattached to the occupant. Thus, when no significant degree of danger isdetected, the first amount of looseness is given to the seatbelt,whereby the occupant does not have a feeling of oppression, and on theother hand, when the significant degree of danger is detected, thesecond amount of looseness is given to the seatbelt, whereby theoccupant can be properly protected. As a result, a comfortable seatbeltattaching feeling can be given to the occupant, while the occupant canbe properly protected.

[0079] To attain the eleventh object, according to a fourteenth aspectof the invention, the danger degree detecting means of the automotivepassenger restraint and protection apparatus according to the thirteenthaspect comprises at least one of vehicle speed detecting means fordetecting traveling speed of the automotive vehicle, braking detectingmeans for detecting stepping-on of a brake pedal of the automotivevehicle, steering angle change rate detecting means for detecting a rateof change in a steering angle of the automotive vehicle, ambientilluminance detecting means for detecting ambient illuminance of theautomotive vehicle, and raindrop detecting means for detecting raindropson the automotive vehicle, the danger degree detecting means detectingthe significant degree of danger if the vehicle speed detecting meansdetects that the traveling speed of the automotive vehicle is higherthan a predetermined value and at the same time at least one ofconditions is satisfied that the stepping-on of the brake pedal isdetected by the braking detecting means, the steering angle change ratedetecting means detects that the rate of change of the steering angleexceeds a predetermined value, the ambient illuminance detecting meansdetects that the ambient illuminance of the automotive vehicle is belowa predetermined value, and the raindrop detecting means detects theraindrops on the automotive vehicle.

[0080] According to the fourteenth aspect, it is possible to accuratelydetermine the degree of danger of collision of the automotive vehicle.

[0081] To attain the twelfth object, according to a fifteenth aspect ofthe invention, various forms of the automotive passenger restraint andprotection apparatus according to the fourteenth aspect are provided asfollows:

[0082] The danger degree detecting means comprises vehicle speeddetecting means for detecting traveling speed of the automotive vehicle,and braking detecting means for detecting a stepping-on force of a brakepedal of the automotive vehicle or stepping-on speed thereof, thecontrol means controlling the motor such that rotational speed of themotor in retracting the seatbelt is higher as the stepping-on force orthe stepping-on speed detected by the braking detecting means is larger,when the traveling speed of the automotive vehicle detected by thevehicle speed detecting means is higher than a predetermined value.

[0083] The danger degree detecting means comprises vehicle speeddetecting means for detecting traveling speed of the automotive vehicle,and braking detecting means for detecting stepping-on of a brake pedalof the automotive vehicle, the control means controlling the motor suchthat rotational speed of the motor in retracting the seatbelt is higheras the traveling speed of the automotive vehicle detected by the vehiclespeed detecting means is higher, when the detected traveling speed ishigher than a predetermined value and at the same time the stepping-onof the brake pedal is detected by the braking detecting means.

[0084] The danger degree detecting means comprises vehicle speeddetecting means for detecting traveling speed of the automotive vehicle,and steering angle change rate detecting means for detecting a rate ofchange in a steering angle of the automotive vehicle, the control meanscontrolling the motor such that rotational speed of the motor inretracting the seatbelt is higher as the rate of change in the steeringangle detected by the steering angle change rate detecting means islarger, when the traveling speed of the automotive vehicle detected bythe vehicle speed detecting means is higher than a predetermined value.

[0085] The danger degree detecting means comprises vehicle speeddetecting means for detecting traveling speed of the automotive vehicle,and steering angle change rate detecting means for detecting a rate ofchange in a steering angle of the automotive vehicle, the control meanscontrolling the motor such that rotational speed of the motor inretracting the seatbelt is higher as the traveling speed of theautomotive vehicle detected by the vehicle speed detecting means ishigher, when the detected traveling speed is higher than a predeterminedvalue and at the same time the rate of change in the steering angledetected by the steering angle change rate detecting means is largerthan a predetermined value.

[0086] The danger degree detecting means comprises vehicle speeddetecting means for detecting traveling speed of the automotive vehicle,and ambient illuminance detecting means for detecting ambientilluminance of the automotive vehicle, the control means controlling themotor such that rotational speed of the motor in retracting the seatbeltis higher as the ambient illuminance detected by the ambient illuminancedetecting means is smaller, when the traveling speed of the automotivevehicle detected by the vehicle speed detecting means is higher than apredetermined value.

[0087] The danger degree detecting means comprises vehicle speeddetecting means for detecting traveling speed of the automotive vehicle,and ambient illuminance detecting means for detecting ambientilluminance of the automotive vehicle, the control means controlling themotor such that rotational speed of the motor in retracting the seatbeltis higher as the traveling speed of the automotive vehicle detected bythe vehicle speed detecting means is higher, when the detected travelingspeed is higher than a predetermined value and at the same time theambient illuminance detected by the ambient illuminance detecting meansis smaller than a predetermined value.

[0088] The danger degree detecting means comprises vehicle speeddetecting means for detecting traveling speed of the automotive vehicle,and raindrop detecting means for detecting raindrop on the automotivevehicle, the control means controlling the motor such that rotationalspeed of the motor in retracting the seatbelt is higher as the travelingspeed of the automotive vehicle detected by the vehicle speed detectingmeans is higher, when the detected traveling speed is higher than apredetermined value and at the same time the raindrops are detected bythe raindrop detecting means.

[0089] The danger degree detecting means comprises vehicle speeddetecting means for detecting traveling speed of the automotive vehicle,and braking detecting means for detecting a stepping-on force of a brakepedal of the automotive vehicle or stepping-on speed thereof, thecontrol means controlling the motor such that an amount of protractionof the seatbelt is smaller as the stepping-on force or the stepping-onspeed detected by the braking detecting means is larger, when thetraveling speed of the automotive vehicle detected by the vehicle speeddetecting means is higher than a predetermined value.

[0090] The danger degree detecting means comprises vehicle speeddetecting means for detecting traveling speed of the automotive vehicle,and braking detecting means for detecting stepping-on of a brake pedalof the automotive vehicle, the control means controlling the motor suchthat an amount of protraction of the seatbelt is smaller as thetraveling speed of the automotive vehicle detected by the vehicle speeddetecting means is higher, when the detected traveling speed is higherthan a predetermined value and at the same time the stepping-on of thebrake pedal is detected by the braking detecting means.

[0091] The danger degree detecting means comprises vehicle speeddetecting means for detecting traveling speed of the automotive vehicle,and steering angle change rate detecting means for detecting a rate ofchange in a steering angle of the automotive vehicle, the control meanscontrolling the motor such that an amount of protraction of the seatbeltis smaller as the rate of change in the steering angle detected by thesteering angle change rate detecting means is larger, when the travelingspeed of the automotive vehicle detected by the vehicle speed detectingmeans is higher than a predetermined value.

[0092] The danger degree detecting means comprises vehicle speeddetecting means for detecting traveling speed of the automotive vehicle,and steering angle change rate detecting means for detecting a rate ofchange in a steering angle of the automotive vehicle, the control meanscontrolling the motor such that an amount of protraction of the seatbeltis smaller as the traveling speed of the automotive vehicle detected bythe vehicle speed detecting means is higher, when the detected travelingspeed is higher than a predetermined value and at the same time the rateof change in the steering angle detected by the steering angle changerate detecting means is larger than a predetermined value.

[0093] The danger degree detecting means comprises vehicle speeddetecting means for detecting traveling speed of the automotive vehicle,and ambient illuminance detecting means for detecting ambientilluminance of the automotive vehicle, the control means controlling themotor such that an amount of protraction of the seatbelt is smaller asthe ambient illuminance detected by the ambient illuminance detectingmeans is smaller, when the traveling speed of the automotive vehicledetected by the vehicle speed detecting means is higher than apredetermined value.

[0094] The danger degree detecting means comprises vehicle speeddetecting means for detecting traveling speed of the automotive vehicle,and ambient illuminance detecting means for detecting ambientilluminance of the automotive vehicle, the control means controlling themotor such that an amount of protraction of the seatbelt is smaller asthe traveling speed of the automotive vehicle detected by the vehiclespeed detecting means is higher, when the detected traveling speed ishigher than a predetermined value and at the same time the ambientilluminance detected by the ambient illuminance detecting means issmaller than a predetermined value.

[0095] The danger degree detecting means comprises vehicle speeddetecting means for detecting traveling speed of the automotive vehicle,and raindrop detecting means for detecting raindrops on the automotivevehicle, the control means controlling the motor such that an amount ofprotraction of the seatbelt is smaller as the traveling speed of theautomotive vehicle detected by the vehicle speed detecting means ishigher, when the detected traveling speed is higher than a predeterminedvalue and at the same time the raindrops are detected by the raindropdetecting means.

[0096] According to the fifteenth aspect, it is possible to properlyprotect the occupant in a manner dependent upon the degree of danger ofcollision of the automotive vehicle.

[0097] To attain the thirteenth object, according to a sixteenth aspectof the invention, there is provided an automotive passenger restraintand protection apparatus for an automotive vehicle, having a seatbelt,for restraining an occupant of the automotive vehicle by the seatbelt toprotect the occupant, comprising an electric retractor having drivingmeans for retracting and protracting the seatbelt, power supply meansfor supplying power to the electric retractor, detecting means fordetecting whether there is a need for supply of power from the powersupply means to the electric retractor, first switching means responsiveto results of detection of the detecting means, for selecting supply ofpower from the power supply means to the electric retractor and stoppageof the supply of power, second switching means for selecting supply ofpower from the power supply means to the electric retractor and stoppageof the supply of power, and monitor control means for monitoring theresults of detection of the detecting means and controlling the secondswitching means in response to the results of detection of the detectingmeans, wherein the monitor control means is responsive to a result ofdetection of the detecting means that there is no need for supply ofpower from the power supply means to the electric retractor after supplyof power from the power supply means to the electric retractor, forcontrolling the second switching means so as to start supply of powerfrom the power supply means to the electric retractor, and following thestart of supply of power by the second switching means, the firstswitching means stops the supply of power to the electric retractor inresponse to the result of detection of the detecting means, and whereinthe monitor control means controls the second switching means so as tostop the supply of power to the electric retractor after lapse of apredetermined time period from the stoppage of the supply of power bythe first switching means.

[0098] According to the sixteenth aspect, when the detecting meansdetects that there is no need for supply of power from the power supplymeans to the electric retractor after supply of power from the powersupply means to the electric retractor, the first switching means stopsthe supply of power to the electric retractor in response to the resultof detection of the detecting means. As a result, wasteful consumptionand deterioration of the battery can be prevented.

[0099] Further, when the detecting means detects that there is no needfor supply of power from the power supply means to the electricretractor after supply of power from the power supply means to theelectric retractor, the monitor control means controls the secondswitching means to start supply of power from the power supply means tothe electric retractor, and after lapse of a predetermined time periodfrom the stoppage of the supply of power by the first switching means,the monitor control means controls the second switching means to stopthe supply of power to the electric retractor. As a result, retractionof the seatbelt can be carried out without fail when the seatbelt isdisconnected from the occupant, to thereby prevent the seatbelt tonguefrom being caught in the door.

[0100] The above and other objects, features, and advantages of theinvention will become more apparent from the following detaileddescription taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0101]FIG. 1 is a block diagram schematically showing the arrangement ofan electric retractor 100 provided in an automotive passenger restraintand protection apparatus according to a first embodiment of theinvention;

[0102]FIG. 2 is a circuit diagram showing the configuration of a DCmotor driver 11 appearing in FIG. 1;

[0103]FIG. 3 is a flowchart showing a fault diagnosis program accordingto the first embodiment, executed by an MPU 14 appearing in FIG. 1;

[0104]FIG. 4A is a graph showing an example of the waveform of voltageacross terminals P3 and P4;

[0105]FIG. 4B is a graph showing another example of the waveform ofvoltage across terminals P3 and P4;

[0106]FIG. 5 is a flowchart showing a fault diagnosis program accordingto a second embodiment of the invention, executed by the MPU 14;

[0107]FIG. 6 is a flowchart showing the configuration of a DC motordriver 11 employed in a third embodiment of the invention;

[0108]FIG. 7 is a flowchart showing a fault diagnosis program accordingto the third embodiment of the invention, executed by the MPU 14;

[0109]FIG. 8 is a flowchart showing a fault diagnosis program accordingto a fourth embodiment of the invention executed by the MPU 14;

[0110]FIG. 9 is a flowchart showing another fault diagnosis programaccording to the fourth embodiment;

[0111]FIG. 10 is a block diagram schematically showing the arrangementof an electric retractor 500 provided in an automotive passengerrestraint and protection apparatus according to a fifth embodiment ofthe invention;

[0112]FIG. 11 is a flowchart showing a main status control programaccording to the fifth embodiment, executed by the MPU 14;

[0113]FIG. 12 is a flowchart showing a status control program executedat a step S1201 in FIG. 11;

[0114]FIG. 13 is a flowchart showing a status control program executedat a step S1202 in FIG. 11;

[0115]FIG. 14 is a flowchart showing a status control program executedat a step S1203 in FIG. 11;

[0116]FIG. 15 is a flowchart showing a status control program executedat a step S1204 in FIG. 11;

[0117]FIG. 16 is a block diagram schematically showing the arrangementof an electric retractor 600 provided in an automotive passengerrestraint and protection apparatus according to a sixth embodiment ofthe invention;

[0118]FIG. 17 is a view showing an example of the waveforms of signalsinput to the MPU 14 when a buckle connection detector 16 is normal;

[0119]FIG. 18 is a flowchart showing seatbelt storing control accordingto the sixth embodiment;

[0120]FIG. 19 is a view showing an example of the waveforms of signalsinput to the MPU 14 when “ON fault” occurs with the seatbeltdisconnected from the occupant;

[0121]FIG. 20 is a flowchart showing a control program according to thesixth embodiment, executed by the MPU 14;

[0122]FIG. 21 is a flowchart showing a continued part of the FIG. 20control;

[0123]FIG. 22 is a flowchart showing timer interrupt processingaccording to the sixth embodiment;

[0124]FIG. 23 is a flowchart showing seatbelt slackening controlaccording to the sixth embodiment;

[0125]FIG. 24 is a view showing an example of the waveforms of signalsinput to the MPU 14 when “ON fault” occurs after the seatbelt shiftsfrom a state attached to the occupant to a state disconnected from theoccupant;

[0126]FIG. 25 is a flowchart showing a control program executed by theMPU 14 according to the sixth embodiment;

[0127]FIG. 26 is a flowchart showing a continued part of the FIG. 25program;

[0128]FIG. 27 is a view showing an example of the waveforms of signalsinput to the MPU 14 when “OFF fault” occurs with the seatbeltdisconnected from the occupant;

[0129]FIG. 28 is a flowchart showing a control program executed by theMPU 14 according to the sixth embodiment;

[0130]FIG. 29 is a view showing an example of the waveforms of signalsinput to the MPU 14 when “OFF fault” occurs after the seatbelt shiftsfrom a state attached to the occupant to a state disconnected from theoccupant;

[0131]FIG. 30 is a flowchart showing a control program executed by theMPU 14 according to the sixth embodiment;

[0132]FIG. 31 is a circuit diagram showing the arrangements of a DCmotor driver 11, a detecting circuit 45 and a buckle connection detector16 according to a seventh embodiment of the invention;

[0133]FIG. 32A is a view showing a change in a signal input to the MPU14 to indicate a normal power consumption mode;

[0134]FIG. 32B is a view showing a change in the signal input to the MPU14 to indicate a reduced power consumption mode;

[0135]FIG. 32C is a view showing a low level at which the signal inputto the MPU 14 is held to indicate no change in the power consumptionmode;

[0136]FIG. 32D is a view showing a high level at which the signal inputto the MPU 14 is held to indicate no change in the power consumptionmode;

[0137]FIG. 33 is a flowchart showing reduced power consumption controlexecuted by the MPU 14 according to the seventh embodiment;

[0138]FIG. 34 is a block diagram showing the arrangement of an electricretractor 800 provided in an automotive passenger restraint andprotection apparatus according to an eighth embodiment of the invention;

[0139]FIG. 35 is a flowchart showing seatbelt storing control accordingto a ninth embodiment of the invention executed by the MPU 14 inretracting the seatbelt;

[0140]FIG. 36 is a flowchart showing seatbelt protraction controlaccording to the ninth embodiment executed by the MPU 14 in protractingthe seatbelt;

[0141]FIG. 37 is a block diagram showing the arrangement of anautomotive passenger restraint and protection apparatus according to atenth embodiment of the invention;

[0142]FIG. 38 is a block diagram showing details of the arrangement ofthe automotive passenger restraint and protection apparatus according tothe tenth embodiment;

[0143]FIG. 39A is a schematic view showing the construction of aseatbelt device with an electric retractor according to the tenthembodiment;

[0144]FIG. 39B is a schematic view showing the construction of theseatbelt device of FIG. 39A, as viewed from a different angle;

[0145]FIG. 40 is a flowchart showing a manner of operation of theautomotive passenger restraint and protection apparatus according to thetenth embodiment;

[0146]FIG. 41A is a diagram showing an example of the waveform ofterminal voltage across the DC motor 10 assumed when the seatbelt isslowly protracted by the occupant;

[0147]FIG. 41B is a diagram showing an example of the waveform ofterminal voltage across the DC motor 10 assumed when the seatbelt isquickly protracted by the occupant;

[0148]FIG. 42 is a flowchart showing a control program according to theeleventh embodiment, executed by the MPU 14;

[0149]FIG. 43 is a block diagram showing the arrangement of anarithmetic processing portion of the apparatus according to the eleventhembodiment;

[0150]FIG. 44 is block diagram showing the arrangement of an electricretractor 1200 according to a twelfth embodiment of the invention;

[0151]FIG. 45 is a schematic view showing the interior of a vehiclecompartment with a brake pedal, which is applied to the twelfthembodiment of the invention;

[0152]FIG. 46 is a flowchart showing a control program according to thetwelfth embodiment, executed by the MPU 14;

[0153]FIG. 47 is a flowchart showing first seatbelt slackening controlaccording to the twelfth embodiment;

[0154]FIG. 48 is a flowchart showing second seatbelt slackening controlaccording to the twelfth embodiment;

[0155]FIG. 49 is a schematic view showing the arrangement of anautomotive passenger restraint and protection apparatus according to athirteenth embodiment of the invention;

[0156]FIG. 50 is a schematic view showing an occupant seat with aseating switch 104;

[0157]FIG. 51 is a schematic view showing the occupant seat as viewedfrom a different angle; and

[0158]FIG. 52 is a schematic sectional view showing the construction ofthe seating switch 104.

DETAILED DESCRIPTION

[0159] The invention will now be described in detail with reference todrawings showing embodiments thereof.

[0160] First Embodiment

[0161] Referring first to FIG. 1, there is shown the arrangement of anelectric retractor 100 provided in an automotive passenger restraint andprotection apparatus according to a first embodiment of the invention.

[0162] The seatbelt retractor 100 has a frame 1 in which is rotatablymounted a reel shaft (takeup shaft) 3 for retracting and protracting aseatbelt. Secured to an end of the reel shaft 3 is a known seatbeltlocking mechanism 2 which is adapted to lock or stop the seatbelt frombeing protracted when a predetermined or higher degree of decelerationis applied to an automotive vehicle in which the present apparatus isinstalled or when the seatbelt is protracted at a predetermined orhigher degree of acceleration.

[0163] The reel shaft 3 has a central shaft 3 a coupled to a centralshaft of a reel shaft pulley 5, which is in turn coupled to a DC motorpulley 6 via a power transmission belt 7.

[0164] The reel shaft pulley 5 and the DC motor pulley 6 each have anouter periphery thereof formed with a predetermined number of outerteeth, while the power transmission belt 7 has an inner peripherythereof formed with a predetermined number of inner teeth which are inmesh with the outer teeth of the reel shaft pulley 5 and the DC motorpulley 6.

[0165] The DC motor pulley 6 has a central shaft thereof coupled to a DCmotor 10 such that the rotation of the DC motor 10 is transmitted to thereel shaft 3 via the DC motor pulley 6.

[0166] The DC motor 10 is fixed to the frame 1 at at least two pointsthereof, and is connected to an MPU (Micro Processing Unit) 14 via a DCmotor driver 11 which rotatively drives the DC motor 10 in response to aPWM (Pulse Width Modulation) signal from the MPU 14.

[0167]FIG. 2 is a circuit diagram showing the construction of the DCmotor driver 11. In FIG. 2, reference numerals P1 and P2 designate inputterminals for the PWM (Pulse Width Modulation) signal from the MPU 14,which has a frequency of 20 kHz, for example. Reference numerals P3 andP4 designate output terminals for detecting current, and P5 and P6output terminals for detecting voltage, the terminals P1 to P6 beingconnected to the MPU 14. Supply voltage from a battery Vb shown in FIG.2 is supplied to the DC motor 10. A plurality of transistors and FETsappearing in FIG. 2 are for selectively causing the DC motor 10 to benormally rotated or reversely rotated in response to the PWM signal fromthe MPU 14. More specifically, the DC motor driver 11 is constructedsuch that if a high-level control signal is delivered through theterminal P1 from the MPU 14, the DC motor 10 is rotated in the normaldirection, whereby the seatbelt is retracted by the reel shaft 3, whileif a high-level control signal delivered through the terminal P2 fromthe MPU 14, the DC motor 10 is rotated in the reverse direction, wherebythe seatbelt is protracted by the reel shaft 3.

[0168] In FIG. 2, reference numeral C1 designates a current detectingcircuit which detects current i flowing to the DC motor 10, based uponcurrent flowing through a resistance r1. The current detecting circuitC1 is comprised of interface circuits (hereinafter abbreviated as “IFs”)IF1 and IF2 which operate to remove current fluctuations or variationsdue to the influence of the PWM signal. The MPU 14 receives voltagesignals from the IFs IF1 and IF2 and detects current i flowing to the DCmotor 10 from these voltage signals.

[0169] In FIG. 2, reference numeral C2 designates a voltage measuringcircuit 2 which measures terminal voltage across the DC motor 10, and iscomprised of IFs IF3 and IF4 which operate to remove fluctuations orvariations in the terminal voltage due to the influence of the PWMsignal. The MPU 14 receives voltage signals from the IFs IF3 and IF4 andmeasures the terminal voltage across the DC motor 10 from these voltagesignals.

[0170] The IFs IF1 to IF4 are each formed by a low-pass filter formed ofa resistance r2, a resistance r3 smaller in resistance value than theresistance r2, and a capacitor c3, all the IFs having a cutoff frequencyof 20 Hz, for example. By virtue of these IFs, the influence of the PWMsignal output from the MPU 14 upon the current detecting circuit C1 andthe voltage measuring circuit C2 is reduced to −60 dB, which is almostnegligible for detection of current by the current detecting circuit C1and detection of terminal voltage by the voltage measuring circuit C2.

[0171] Referring back to FIG. 1, the MPU 14 has a built-in timer 21 formeasuring time. Connected to the MPU 14 are a buckle connection detector16 which detects whether a tongue of the seatbelt has been attached toor mounted on the buckle and whether the tongue of the seatbelt has beendisconnected from the buckle, and a temperature sensor 19 which detectstemperature in the vicinity of the DC motor 10 or the temperature of theDC motor 10 itself.

[0172]FIG. 3 is a flowchart showing a fault diagnosis program executedby the MPU 14.

[0173] First, a flag FLAG, which, when set to 1, indicates that the DCmotor driver 11 functions abnormally, and when set to 0, indicates thatthe DC motor driver 11 functions normally, is reset to 0 at a step S301.

[0174] Then, a high-level signal, for example, a single pulse having arectangular waveform and a pulse width of 0.5 ms is applied to theterminal P1 at a step S302, and the lapse of a predetermined time period(e.g. 0.2 ms) is waited after the application of the high-level signalat a step S303. Then, terminal voltage Va is measured from a value ofcurrent flowing between the terminals P3 and P4 at a step S304, and itis determined at a step S305 whether the measured terminal voltage Vafalls within a range between 4 volts and 6 volts. An example of theterminal voltage between the terminals P3 and P4 is shown in FIG. 4A.

[0175] If the measured terminal voltage Va does not fall within therange between 4 volts and 6 volts, the flag FLAG is set to 1 at a stepS309, followed by terminating the present processing. If the measuredterminal voltage Va falls within the above range, the lapse of apredetermined time period (e.g. 0.4 ms) is waited at a step S306. Duringthe waiting, the flag FLAG is held at 0 to indicate that the DC motordriver 11 is normal.

[0176] Then, terminal voltage Vb is again measured from a value ofcurrent then flowing between the terminals P3 and P4 at a step S307,followed by determining at a step S308 whether the measured terminalvoltage Vb falls within a range between 3 volts and 5 volts. If it isdetermined at the step S308 that the measured terminal voltage Va doesnot fall within the above range, the flag FLAG is set to 1 at the stepS309, followed by terminating the present processing. On the other hand,if it is determined that the measured terminal voltage Vb falls withinthe range between 3 volts and 5 volts, the flag FLAG is held at 0,followed by terminating the present processing.

[0177] The MPU 14 notifies the occupant through a display device or awarning light (not shown) whether the DC motor driver 11 is normal orabnormal, based upon the value of the flag FLAG which indicates resultsof the above described fault diagnosis. In the above described manner,the MPU 14 can perform fault diagnosis of the DC motor driver 16including characteristics of the DC motor 10.

[0178] Although in the above described fault diagnosis program, the MPU14 applies the high-level signal to the DC motor driver 11 through theinput terminal P1, a similar fault diagnosis program is also executed bythe MPU 14 by applying a high-level signal to the DC motor driver 16through the other input terminal P2.

[0179] As described above, according to the first embodiment, after thehigh-level signal, e.g. a single pulse with a pulse width of 0.5 ms isapplied from the MPU to the input terminal P1 to the DC motor driver 11,two kinds of the terminal voltage Va and Vb are measured based uponcurrent flowing between the terminals P3 and P4, to determine, basedupon the measured terminal voltage Va and Vb, whether the DC motordriver 11 is normal or abnormal. As a result, accurate fault diagnosiscan be carried out. Further, based upon the value of the flag FLAG,results of the fault diagnosis are notified to the occupant by means ofa display device or a warning light, whereby the occupant can notice afault of the DC motor driver 11 and take appropriate measures.

[0180] Although in the present embodiment the terminal voltage ismeasured twice based upon current flowing between the terminals P3 andP4, the terminal voltage may be measured only once or three times ormore. If the number of times of measurement is increased, more accuratefault diagnosis can be achieved.

[0181] Second to thirteenth embodiments of the invention will bedescribed hereinbelow. In the description of these embodiments, elementsand parts as well as steps corresponding to those in the firstembodiment described above are designated by identical referencenumerals, detailed description of which is omitted. In the following,only those which differ from the first embodiment will be described.

[0182] Second Embodiment

[0183] An automotive passenger restraint and protection apparatusaccording to a second embodiment of the invention includes an electricretractor which is identical in construction with the electric retractor100 of the first embodiment described above, description of which istherefore omitted. The second embodiment is distinguished from the firstembodiment only in the manner of fault diagnosis executed by the MPU 14.

[0184] A manner of fault diagnosis according to the present embodiment,executed by the MPU 14 will be described hereinbelow.

[0185]FIG. 5 is a flowchart showing a fault diagnosis program accordingto the present embodiment, executed by the MPU 14.

[0186] First, the flag FLAG is reset to 0 at a step S501. Then, a signalof a TTL (Transistor Transistor Level) level having a frequency of 10kHz and a duty factor of 10%, for example is applied to the terminal P1at a step S502, and the lapse of a predetermined time period (e.g. 1sec) is waited after the application of the TTL level signal at a stepS503. An example of the waveform of terminal voltage then appliedbetween the terminals P3 and P4 is shown in FIG. 4B.

[0187] Then, terminal voltage Vc is measured from a value of currentflowing between the terminals P3 and P4 at a step S504, followed bystopping the application of the TTL level signal to the terminal P1 at astep S505. Then, it is determined at a step S506 whether the measuredterminal voltage Vc falls within a range between 0.5 volts and 2 volts.

[0188] If the measured terminal voltage Vc does not fall within therange between 0.5 volts and 2 volts, the flag FLAG is set to 1 at a stepS507, followed by terminating the present processing. If the measuredterminal voltage Vc falls within the above range, the flag FLAG is heldat 0 to indicate that the DC motor driver 11 is normal, followed byterminating the present processing.

[0189] The MPU 14 notifies the occupant through a display device or awarning light (not shown) whether the DC motor driver 11 is normal orabnormal, based upon the value of the flag FLAG which indicates resultsof the above described fault diagnosis. In the above described manner,the MPU 14 can perform fault diagnosis of the DC motor driver 16including characteristics of the DC motor 10.

[0190] Although in the above described fault diagnosis program, the MPU14 applies the TTL level signal to the DC motor driver 11 through theinput terminal P1, a similar fault diagnosis program is also executed bythe MPU 14 by applying a TTL level signal to the DC motor driver 16through the other input terminal P2.

[0191] As described above, according to the second embodiment, after theapplication of a TTL level signal having a frequency of 10 kHz and aduty factor of 10%, for example, to the terminal P1, terminal voltage Vcis measured from a value of current flowing between the terminals P3 andP4, to determine whether the measured terminal voltage Vc falls within apredetermined range. Based upon results of the determination, whetherthe DC motor driver 11 is normal or abnormal is determined. As a result,accurate fault diagnosis can be carried out. Further, based upon thevalue of the flag FLAG, results of the fault diagnosis are notified tothe occupant by means of a display device or a warning light, wherebythe occupant can notice a fault of the DC motor driver 11 and takeappropriate measures.

[0192] Third Embodiment

[0193] An automotive passenger restraint and protection apparatusaccording to a third embodiment of the invention includes an electricretractor 300 which is distinguished from the electric retractor 100 ofthe first embodiment only in the construction of the DC motor driver 11.Except for this, the construction of the electric retractor 300 isidentical with the electric retractor, description of which is thereforeomitted.

[0194]FIG. 6 is a circuit diagram of the construction of the DC motordriver 11 according to the present embodiment.

[0195] The construction of the DC motor driver 11 employed in thepresent embodiment is distinguished from that of the DC motor driver 11employed in the first embodiment (FIG. 2) in that the IFs IF3 and IF4are omitted, and a load 12 for use in the fault diagnosis is connectedin parallel with the DC motor 10, and a switch 13 is provided forselecting the DC motor 10 or the load 12. The load has loadcharacteristics equivalent to electrical characteristics of the DC motor10. Except for these points, the construction of the DC motor driver 11of the present embodiment is identical with that shown in FIG. 2,description of which is therefore omitted.

[0196] The switch 13 is adapted to operate in response to a controlsignal from the MPU 14 to be selectively connected to the DC motor 10side or to the load 12 side.

[0197]FIG. 7 is a flowchart showing a fault diagnosis program executedby the MPU 14.

[0198] First, the flag FLAG is reset to 0 at a step S701.

[0199] Then, the switch 13 is connected to the load 12 side at a stepS702, and a high-level signal, for example, a single pulse having arectangular waveform and a pulse width of 0.5 ms, is applied to theterminal P1 at a step S703. Then, terminal voltage Va is measured from avalue of current flowing between the terminals P3 and P4 at a step S704,followed by applying a low-level signal to the terminal P1 at a stepS705.

[0200] Then, the switch 13 is connected to the DC motor 10 side at astep S706, and then again a high-level signal, for example, a singlepulse having a rectangular waveform and a pulse width of 0.5 ms, isapplied to the terminal P1 at a step S707. Then, terminal voltage Vb ismeasured based upon a value of current flowing between the terminals P3and P4 at a step S708, followed by applying a low-level signal to theterminal P1 at a step S709.

[0201] Then, it is determined at a step S710 whether the absolute valueof the difference between the measured terminal voltage Va and themeasured terminal voltage Vb is larger than a predetermined value. Thepredetermined value is set based upon temperature in the vicinity of theDC motor 10 and the load 12 or the temperature of the DC motor 10 andthe load 12 themselves.

[0202] If it is determined at the step S710 that the absolute value isnot larger than the predetermined value, the present program isterminated so that the flag FLAG is held at 0, whereas if the absolutevalue is not larger than the predetermined value, the flag FLAG is setto 1 at a step S711, followed by terminating the present processing.

[0203] The MPU 14 notifies the occupant through a display device or awarning light (not shown) whether the DC motor driver 11 is normal orabnormal, based upon the value of the flag FLAG which indicates resultsof the above described fault diagnosis. In the above described manner,the MPU 14 can perform fault diagnosis of the DC motor driver 16including characteristics of the DC motor 10.

[0204] Although in the above described fault diagnosis program, the MPU14 applies the high-level signal and low-level signal to the DC motordriver 11 through the input terminal P1, a similar fault diagnosisprogram is also executed by the MPU 14 by applying a high-level signaland a low-level signal to the DC motor driver 16 through the other inputterminal P2.

[0205] As described above, according to the third embodiment, terminalvoltage Va applied when the load 12 is connected and terminal voltage Vbapplied when the DC motor 10 is connected are measured, and based uponwhether the absolute value of the difference between the measuredterminal voltage Va and the measured terminal voltage Vb, it isdetermined whether the DC motor driver 11 is normal or abnormal. As aresult, accurate fault diagnosis can be carried out. Further, results ofthe fault diagnosis are notified to the occupant by means of a displaydevice or a warning light, whereby the occupant can notice a fault ofthe DC motor driver 11 and take appropriate measures.

[0206] Although in the third embodiment, as the high-level signal, asingle pulse having a pulse width of 0.5 ms is applied (steps S703 andS707), a pulse train having a frequency of 10 kHz and a duty factor of10%, for example, may be applied, instead.

[0207] Fourth Embodiment

[0208] An automotive passenger restraint and protection apparatusaccording to a fourth embodiment of the invention includes an electricretractor 400 which is distinguished from the electric retractor 100 ofFIG. 1 in that a warning device is connected to the MPU 14 for givingwarning by means of a warning buzzer, a warning light or the like, inplace of the temperature sensor 19 shown in FIG. 1, and except for this,the construction of the electric retractor 400 is identical with that ofFIG. 1, illustration and description of which are therefore omitted.

[0209]FIG. 8 is a flowchart showing a fault diagnosis program accordingto the fourth embodiment, executed by the MPU 14. This program is storedin a memory, not shown, within the MPU 14 and executed at predeterminedtime intervals t1 (e.g. 15 sec).

[0210] First, terminal voltage V across the DC motor 10 is measured bythe voltage detecting circuit C2 and at the same time the timer 15 isstarted to measure elapsed time at a step S801.

[0211] Then, it is determined at a step S802 whether the measuredterminal voltage V has continuously fallen within a range between afirst predetermined value V1 (e.g. 5 volts) and a second predeterminedvalue V2 (e.g. 10 volts) over a predetermined time period t2 (e.g. 10sec). The first and second predetermined values V1 and V2 are bothhigher than a range assumed when the DC motor 10 and the DC motor driver11 are functioning normally, but are set to values defining a range tobe assumed when the DC motor 0.10 runs idle due to abnormality of thepower transmission mechanism or the like and the DC motor 10 and the DCmotor driver 11 are not truly faulty. In the following description, theterm “fault” indicates a state where the DC motor 10 runs idle due toabnormality of the power transmission mechanism or the like. If themeasured terminal voltage V has not continuously fallen within the rangebetween the first predetermined value V1 and the second predeterminedvalue V2 over the predetermined time period t2, it is determined thatthere is no “fault”, and then the present program is immediatelyterminated, whereas if the measured terminal voltage V has continuouslyfallen within the range between the first predetermined value V1 and thesecond predetermined value V2 over the predetermined time period t2, itis determined that there is a “fault”, and then a PWM signal isdelivered from the MPU 14 to the DC motor driver 11 to stop the drivingof the DC motor 10 at a step S803, and a control signal is deliveredfrom the MPU 14 to the warning device to give warning by the warningbuzzer, the warning light or the like at a step S804, followed byterminating the present processing.

[0212]FIG. 9 is a flowchart showing another fault diagnosis programaccording to the present embodiment. This program is stored in a memory,not shown, within the MPU 14 and executed at predetermined timeintervals t1 (e.g. 15 sec).

[0213] First, current i flowing to the DC motor 10 is measured by thecurrent detecting circuit C1 and at the same time the timer 15 isstarted to measure elapsed time at a step S901.

[0214] Then, it is determined at a step S902 whether the measuredcurrent i has continuously fallen within a range between a firstpredetermined value i1 (e.g. 2 amperes) and a second predetermined valuei2 (e.g. 4 amperes) over a predetermined time period t3 (e.g. 10 sec).The first and second predetermined values i1 and i2 are both larger thana range assumed when the DC motor 10 and the DC motor driver 11 arefunctioning normally, but are set to values defining a range to beassumed when the DC motor 10 runs idle due to abnormality of the powertransmission mechanism or the like and the DC motor 10 and the DC motordriver 11 are not truly faulty. In the following description, the term“fault” indicates a state where the DC motor 10 runs idle due toabnormality of the power transmission mechanism or the like. If themeasured current i has not continuously fallen within the range betweenthe first predetermined value i1 and the second predetermined value i2over the predetermined time period t3, it is determined that there is no“fault”, and then the present program is immediately terminated, whereasif the measured current i has continuously fallen within the rangebetween the first predetermined value i1 and the second predeterminedvalue i2 over the predetermined time period t3, it is determined thatthere is a “fault”, and then the processing proceeds to a step S903. Thestep S903 and a step S904 are identical with the above described stepsS803 and S804 of FIG. 8, description of which is therefore omitted.

[0215] As described above, according to the present embodiment, if theterminal voltage V has continued to fall within the range between thefirst and second predetermined values V1 and V2 to be assumed when theDC motor 10 runs idle due to abnormality of the power transmissionmechanism or the like, over the predetermined time period t2, or if thecurrent i has continued to fall within the range between the first andsecond predetermined values i1 and i2 to be assumed when the DC motor 10runs idle due to abnormality of the power transmission mechanism or thelike, over the predetermined time period t3, it is determined that thereis a “fault”, that is, the DC motor 10 has been running idle for aconsiderable time period so that the DC motor 10 or the DC motor driver11 can subsequently become truly faulty, and a warning is given by thewarning device. As a result, accurate fault diagnosis can be achievedand the detected fault can be notified to the occupant.

[0216] As a variation of the present embodiment, the determination ofthe step S802 of FIG. 8 and that of the step S902 of FIG. 9 may becombined together to carry out both of these determinations. Forexample, it may be determined that there is a “fault” if the measuredterminal voltage V has continuously fallen within the range between thefirst predetermined value V1 and the second predetermined value V2 overthe predetermined time period t2 and at the same time the measuredcurrent i has continuously fallen within the range between the firstpredetermined value i1 and the second predetermined value i2 over thepredetermined time period t3.

[0217] Fifth Embodiment

[0218] An electric retractor 500 provided in an automotive passengerrestraint and protection apparatus according to a fifth embodiment ofthe invention is distinguished from the electric retractor of FIG. 1 inthat a torque sensor 4, a tension sensor 9, and a warning device 7 areadditionally provided.

[0219] The electric retractor 500 according to the fifth embodiment willnow be described with reference to FIG. 10 showing the arrangement ofthe same.

[0220] As shown in FIG. 10, the electric retractor 500 includes thetorque sensor 4, the tension sensor 9, the warning device 17, the buckleconnection detector 16, and the temperature sensor 19, which areconnected to the MPU 14.

[0221] The warning device 17 is for giving warning when an abnormalityof the DC motor 10 is detected by the MPU 14 in a manner describedhereinafter.

[0222] The tension sensor 9 senses tension α of the seatbelt 8 anddelivers a signal indicative of the sensed tension α to the MPU 14. Thetorque sensor 4 senses rotational torque β of the reel shaft 3 anddelivers a signal indicative of the sensed rotational torque β to theMPU 14.

[0223] The construction of the DC motor driver 11 employed in the fifthembodiment is identical with that shown in FIG. 1, except that a switchis provided between the battery Vb and the DC motor 10, for selectivelyconnecting or disconnecting the former to or from the latter to supplyof the supply voltage to the DC motor 10 or stop the supply.Illustration of the construction of the DC motor driver 11 is thereforeomitted.

[0224]FIG. 11 is a flowchart showing a main status control programaccording to the fifth embodiment, executed by the MPU 14. This controlprogram is executed every predetermined time period.

[0225] First, status control is executed based upon results of adetermination of the current i flowing to the DC motor 10 at a stepS1201. Details of the status control will be described with reference toFIG. 12. Upon the start of the status control at the step S1201, thetimer 15 starts measuring time t elapsed after the start of execution ofthe status control program at the step S1201.

[0226] Then, status control is executed based upon results of thedetection of the tension α of the seatbelt 8 by the tension sensor 9 ata step S1202. Details of the status control at the step S1202 will bedescribed with reference to FIG. 13. Upon the start of the statuscontrol at the step S1202, the timer 15 starts measuring time t elapsedafter the start of execution of the status control program at the stepS1202.

[0227] Then, status control is executed based upon results of thedetection of the rotational torque β of the reel shaft 3 by the torquesensor 4 at a step S1203. Details of the status control at the stepS1203 will be described with reference to FIG. 14. Upon the start of thestatus control at the step S1203, the timer 15 starts measuring time telapsed after the start of execution of the status control program atthe step S1203.

[0228] Lastly, status control is executed based upon results of thetemperature γ of the temperature in the vicinity of the DC motor 10 orthe temperature of the DC motor 10 itself at a step. S1204, followed bythe program returning to the step S1201. Details of the status controlat the step S1204 will be described with reference to FIG. 15. Upon thestart of the status control at the step S1204, the timer 15 startsmeasuring time t elapsed after the start of execution of the statuscontrol program at the step S1204.

[0229]FIG. 12 is a flowchart showing the status control program executedat the step S1201.

[0230] First, the current i flowing to the DC motor 10 is detected bythe current detecting circuit C1 at a step S1301, and it is determinedwhether the detected current i exceeds a predetermined value (e.g. 1.4amperes). If the current i does not exceed the predetermined value, itis determined that the DC motor 10 is functioning normally, and then thetime t measured by the timer 15 after the start of the present statuscontrol program is reset to 0 at a step S1304, followed by terminatingthe present processing. On the other hand, if the detected current iexceeds the predetermined value, the value of the timer 15 isincremented by 1 at a step S1303.

[0231] Then, it is determined at a step S1305 whether the elapsed time texceeds a predetermined time period t (e.g. 60 sec). If the former doesnot exceed the latter, it is determined that the DC motor 10 isfunctioning normally, and the present program is immediately terminated,whereas if the former exceeds the latter, it is determined that the DCmotor 10 is abnormal, and then the switch 35 of the DC motor driver 11is operated to stop the supply of the supply voltage from the battery Vbto the DC motor 10 at a step S1306, followed by terminating the presentprocessing.

[0232] According to the above status control program (step S1201), ifthe current i flowing to the DC motor 10 has continued to exceed thepredetermined value (1.4 amperes) over the predetermined time period (60sec), it is determined that the DC motor 10 is abnormal, and then thesupply of the supply voltage from the battery Vb to the DC motor 10 isstopped. Therefore, it is possible to prevent the DC motor 10 frombecoming faulty.

[0233]FIG. 13 is a flowchart showing the status control program executedat the step S1202.

[0234] First, the tension α of the seatbelt 8 is sensed by the tensionsensor 9 at a step S1401, and it is determined at a step S1402 whetherthe sensed tension a is larger than a predetermined value (e.g. 12 mN).If the sensed tension α is not larger than the predetermined value, itis determined that the DC motor 10 is functioning normally, and then theprocessing proceeds to a step S1404. On the other hand, if the sensedtension α is larger than the predetermined value, the processingproceeds to a step S1403. The steps S1403 to S1406 are identical withthe steps S1303 to S1306 of FIG. 12 described above, description ofwhich is therefore omitted.

[0235] According to the above status control program (step S1202), ifthe sensed tension α has continued to be larger than the predeterminedvalue (12 mN) over the predetermined time period (60 sec), it isdetermined that the DC motor 10 is abnormal, and then the supply of thesupply voltage from the battery Vb to the DC motor 10 is stopped.Therefore, it is possible to prevent the DC motor 10 from becomingfaulty.

[0236]FIG. 14 is a flowchart showing the status control program executedat the step S1203.

[0237] First, the rotational torque β of the reel shaft 3 is sensed bythe torque sensor 4 at a step S1501, and it is determined at a stepS1502 whether the sensed rotational torque β is larger than apredetermined value (e.g. 30 mN cm). If the sensed rotational torque βis not larger than the predetermined value, it is determined that the DCmotor 10 is normal, and then the processing proceeds to a step S1504,whereas if the sensed rotational torque β is larger than thepredetermined value, the processing proceeds to a step S1503. The stepsS1503 to S1506 are identical with the steps S1303 to S1306 of FIG. 12described above, description of which is therefore omitted.

[0238] According to the above status control program (step S1203), ifthe sensed rotational torque β has continued to be larger than thepredetermined value (30 mN·cm) over the predetermined time period (60sec), it is determined that the DC motor 10 is abnormal, and then thesupply of the supply voltage from the battery Vb to the DC motor 10 isstopped. Therefore, it is possible to prevent the DC motor 10 frombecoming faulty.

[0239]FIG. 15 is a flowchart showing the status control program executedat the step S1204.

[0240] First, the temperature γ in the vicinity of the DC motor 10 orthe temperature of the DC motor 10 itself is sensed by the temperaturesensor 19 at a step S1601, and it is determined at a step S1602 whetherthe sensed temperature γ exceeds a predetermined value (e.g. 100° C.) Ifthe sensed temperature γ does not exceed the predetermined value, it isdetermined that the DC motor 10 is normal, and then the processingproceeds to a step S1604, whereas if the sensed temperature γ exceedsthe predetermined value, the processing proceeds to a step S1603. Thesteps S1603 to S1606 are identical with the steps S1303 to S1306 of FIG.12 described above, description of which is therefore omitted.

[0241] According to the above status control program (step S1204), ifthe sensed temperature γ has continued to exceed the predetermined value(100° C.) over the predetermined time period (60 sec), it is determinedthat the DC motor 10 is abnormal, and then the supply of the supplyvoltage from the battery Vb to the DC motor 10 is stopped. Therefore, itis possible to prevent the DC motor 10 from becoming faulty.

[0242] Although in the above described steps S1306, S1406, S1506, andS1606, when it is determined that the DC motor 10 is abnormal, and thesupply of the supply voltage to the DC motor 10 is stopped by means ofthe switch, alternatively a transformer or the like may be provided andthe supply voltage from the battery Vb to the DC motor 10 may bedecreased by the transformer or the like.

[0243] Further, in addition to stopping the supply of the supply voltageto the DC motor 10 or decreasing the supply voltage, the warning device17 may be actuated to give warning to notify the occupant of theabnormal state of the DC motor 10.

[0244] Further alternatively, a control signal in the form of a pulsesignal may be delivered from the MPU 14 through the terminal P1 in FIG.2 to the DC motor driver 11, and if it is determined that the DC motor10 is abnormal, the pulse width, i.e. duty factor of the pulse signalmay be varied. More specifically, the duty factor of the pulse signal isdecreased. This provides substantially the same results as decreasingthe supply voltage to the DC motor 10.

[0245] Furthermore, a high-level signal may be delivered as the controlsignal from the MPU 14 through the terminal P2 in FIG. 2 to the DC motordriver 11 when it is determined that the DC motor 10 is normal, and whenit is determined that the DC motor 10 is abnormal, and a low-levelsignal may be delivered from the MPU 14 through the terminal P2 to theDC motor driver 11 when it is determined that the DC motor 10 isabnormal. This causes a decrease in the current flowing to the DC motor10, providing substantially the same results as decreasing the supplyvoltage to the DC motor 10.

[0246] The parameters used for the abnormality determination, i.e.current i, tension α, rotational torque β, and temperature γ are merelyillustrative and not limitative.

[0247] Sixth Embodiment

[0248]FIG. 16 shows the construction of an electric retractor 600provided in an automotive passenger restraint and protection apparatusaccording to a sixth embodiment of the invention, which is distinguishedfrom the electric retractor 100 of FIG. 1 only in that a winding amountdetector 37, a warning device 38, a collision predictor 41, and avehicle sensor 42, which are connected to the MPU 14, in place of thetemperature sensor 19.

[0249] The following description relates to these component elements 16,37, 38, 41, and 42 and the MPU. The construction of the other componentelements is identical with that of those of the electric retractor 100,description of which is therefore omitted.

[0250] The MPU 14 has built-in timers 15, 39 and 40 for measuringelapsed time. The winding amount detector 37 detects an amount ofwinding of the seatbelt, i.e. an amount of winding of the seatbelt onthe reel shaft 3. The collision predictor 41 detects whether there is afear of a collision of the automotive vehicle or a collision of theautomotive vehicle is unavoidable. The vehicle speed sensor 42 sensesthe traveling speed of the automotive vehicle.

[0251] The MPU 14 has a memory, not shown, which stores programs such ascontrol programs, and a vibration flag used to cause vibration of theseatbelt by alternately protracting and retracting the seatbelt throughexecution of programs.

[0252] The buckle connection detector 16 detects whether the tongue ofthe seatbelt has been attached to or disconnected from the buckle, anddelivers an ON signal when it detects that the seatbelt tongue has beenattached to the buckle, and an OFF signal when it detects that theseatbelt tongue has been disconnected from the buckle.

[0253] The winding amount detector 37 does not detect a specific valueof the winding amount, but determines whether the thickness of a portionof the seatbelt wound on the reel shaft 3 exceeds a predetermined value.It delivers an ON signal to the MPU 14 when the thickness exceeds thepredetermined value, whereas it delivers an OFF signal to the MPU 14when the thickness does not exceed the predetermined value. Thepredetermined value is set to a value intermediate between an amount ofwinding or retraction to be assumed when the seatbelt is in a stored orfully retracted state and an amount of winding or retraction to beassumed when the seatbelt is in a state attached to the occupant.

[0254]FIG. 17 is a view showing an example of the waveforms of signalsinput to the MPU 14 when the buckle connection detector 16 is normal.

[0255] At a time point when the occupant starts protracting the seatbeltin order to mount the seatbelt onto his body, the ON signal from thewinding amount detector 37 has already been delivered to the MPU 14 andalso the OFF signal from the buckle connection detector 16 has alreadybeen delivered to the MPU 14. If the occupant then further protracts theseatbelt so that the winding amount decreases below the predeterminedvalue, the winding amount detector 37 starts delivering the OFF signal.Thereafter, when the seatbelt has become attached to the occupant, thatis, the seatbelt has been attached to the buckle, the buckle connectiondetector 16 starts delivering the ON signal. At this time, the windingamount detector 37 continues delivering the OFF signal.

[0256] Subsequently, when the seatbelt is disconnected from theoccupant, that is, the seatbelt tongue is disconnected from the buckle,the signal received from the buckle connection detector 16 changes fromthe ON signal to the OFF signal. At this time, the MPU 14 startsseatbelt storing control to start retracting the seatbelt. When thewinding amount of the seatbelt increases above the predetermined value,the signal received from the winding amount detector 37 changes from theOFF signal to the ON signal.

[0257]FIG. 18 is a flowchart showing the seatbelt storing control.

[0258] First, the MPU 14 delivers a PWM signal to the DC motor driver 11to thereby rotate the DC motor 10 in the seatbelt retracting directionat a step S1901. It is then determined at a step S1902 whether theretraction of the seatbelt has reached its limit, base upon the currentflowing to the DC motor 10. If the retraction of the seatbelt has notreached its limit, that is, the seatbelt can still be retracted by theDC motor 10, the processing returns to the step S1901, whereas if theretraction of the seatbelt has reached its limit, the present processingis terminated. The expression “the retraction of the seatbelt hasreached its limit” means that the DC motor 10 ceases to rotate in theseatbelt retracting direction.

[0259] Now, description will be made of processing executed by the MPU14 in the event that the buckle connection detector 16 continuesdelivering the ON signal even when the seatbelt is in a statedisconnected from the buckle (hereinafter referred to as “ON fault”).

[0260]FIG. 19 shows an example of the waveforms of signals input to theMPU 14 when “ON fault” occurs with the seatbelt disconnected from theoccupant. FIGS. 20 and 21 are flowcharts showing a control programexecuted by the MPU 14. This control program is started when the ONsignal is delivered from the winding amount detector 37 to the MPU 14and at the same time the ON signal is delivered from the buckleconnection detector 16 to the MPU 14.

[0261] First, a counter n for use in the present control program isreset to 0 and a seatbelt storage flag is reset at a step S2101. It isthen determined at a step S2102 whether the seatbelt is beingprotracted, from the terminal voltage across the DC motor 10. If theseatbelt is not being protracted, the same determination is repeated,whereas if the seatbelt is being protracted, it is determined at a stepS2103 whether the signal received from the winding amount detector 37has changed from the ON signal to the OFF signal. If no change hasoccurred in the received signal, it is determined at a step S2104whether the protraction of the seatbelt has been terminated, from theterminal voltage across the DC motor 10.

[0262] If the protraction of the seatbelt has not been terminated, theprocessing returns to the step S2103, whereas if the protraction of theseatbelt has been terminated, the processing proceeds to a step S2132 toexecute seatbelt storing control, described hereinafter. If it isdetermined at the step S2103 that the signal received from the windingamount detector 37 has changed from the ON signal to the OFF signal, itis determined at a step S2105 whether the signal received from thebuckle connection detector 16 is the ON signal. If it is the OFF signal,it is determined that there is no ON fault, and then, after the lapse ofa predetermined time period t1, it is determined at a step S2106 whetherthe signal received from the buckle connection detector 16 is the ONsignal.

[0263] If the signal from the buckle connection detector 16 is the OFFsignal, the timer 15 is started at a step S2112, and then it isdetermined at a step S2113 whether the seatbelt has been protracted,from the terminal voltage across the DC motor 10. If the seatbelt hasbeen protracted, the timer 15 is stopped and cleared at a step S2114,and the seatbelt storage flag is set at a step S2115, followed by theprocessing returning to the step S2102. On the other hand, if theseatbelt has not been protracted, it is determined at a step S2116whether a predetermined time period t2 (e.g. 4 sec) has elapsed, fromthe value of the timer 15. If the predetermined time period t2 has notelapsed, the processing returns to the step S2113, whereas if thepredetermined time period t2 has elapsed, the timer 15 is stopped andcleared at a step S2117, and it is determined at a step S2118 whetherthe seatbelt storage flag has been set.

[0264] If the seatbelt storage flag has been set, the same flag is resetat a step S2119, and then the seatbelt storing control of FIG. 18 isexecuted at a step S2120, followed by the processing returning to thestep S2102.

[0265] If it is determined at the step S2118 that the seatbelt storageflag has not been set, it is determined at a step S2121 whether thecount value of the counter n has reached a predetermined value (e.g. 5).If the count value has reached the predetermined value, the processingreturns to the step S2102, whereas if the count value has not reachedthe predetermined value, the seatbelt storing control is executed at astep S2122, similarly to the step S2120. After completion of theseatbelt storing control, the count value of the counter n isincremented by 1 at a step S2123, followed by the processing returningto the step S2102.

[0266] If it is determined at the step S2106 that attaching of theseatbelt to the buckle has been detected from the signal from the buckleconnection detector 16, a timer interrupt triggered in response to thevalue of the timer 22 is made effective at a step S2107, whereby timerinterrupt processing is executed at predetermined time intervals (e.g.0.1 sec), as described hereinbelow.

[0267]FIG. 22 is a flowchart showing the timer interrupt processing.

[0268] First, upon the start of execution of the timer interruptprocessing, the timer interrupt is made ineffective at a step S2301.Then, it is determined at a step S2302 whether attaching of the seatbelttongue to the buckle has been detected by the buckle connection detector16. If attaching of the seatbelt has not been detected, the counter n isreset to 0 and the seatbelt storage flag is reset at a step S2303, andthen the program jumps to a step S2304 to execute the seatbelt storingcontrol of the step S2120.

[0269] On the other hand, if it is determined at the step S2302 thatattaching of the seatbelt has been detected, it is determined at a stepS2305 whether an output signal from the collision predictor 41 has beenreceived, which indicates that a collision of the vehicle isunavoidable. If the output signal has been received, a PWM signal isdelivered to the DC motor driver 11 over a predetermined time period t3(e.g. 4 sec) which is measured by the timer 40, to rotate the DC motor10 in the seatbelt retracting direction at a step S2306. Thus, theoccupant can be properly protected in the event of a collision of thevehicle. Then, the timer interrupt is made effective at a step S2307,and the processing proceeds to the step S2108 (step S2308).

[0270] If it is determined at the step S2305 that the output signalindicative of a collision of the vehicle being unavoidable has not beenreceived, it is determined at a step S2309 whether an output signal fromthe collision predictor 41 has been received, which indicates that thereis a fear of a collision of the vehicle. If the output signal has beenreceived, a PWM signal is delivered to the DC motor driver 11 to rotatethe DC motor 10 alternately in the seatbelt protracting direction and inthe seatbelt retracting direction to vibrate the seatbelt, and thevibration flag is set at a step S2310. The frequency of the vibrationvaries from 1 Hz to 10 kHz so as to provide a vibration which theoccupant can easily feel as a warning. Then, the processing returns tothe step S2305 while the vibration is continued.

[0271] If it is determined at the step S2309 that the output signalindicative of the fear of a collision of the vehicle has not beenreceived, it is determined at a step S2311 whether the seatbelt has beenbeing vibrated, from the state of the vibration flag. If the seatbelthas been being vibrated, the vibration flag is reset and the vibrationis stopped at a step S2312, and then the processing proceeds to the stepS2307. If the seatbelt has not been being vibrated, the timer interruptis made effective at a step S2313, and then the program return to a stepwhere the timer interrupt was input.

[0272] Referring back to FIG. 21, the processing then proceeds to thestep S2308 to execute seatbelt slackening control to give a properamount of looseness to the occupant so as not to give him a feeling ofoppression.

[0273]FIG. 23 is a flowchart of the seatbelt slackening control.

[0274] First, a PWM signal is delivered from the MPU 14 to the DC motordriver 11 to rotate the DC motor 10 in the seatbelt retracting directionat a step S2401, and it is determined at a step S2402 whether theretraction of the seatbelt has reached its limit, based upon the currentflowing to the DC motor 10. When the retraction of the seatbelt hasreached its limit, an improper amount of looseness of the seatbelt canbe once completely removed.

[0275] If it is determined at the step S2402 that the retraction of theseatbelt has not reached its limit, the processing returns to the stepS2401, whereas if it has reached the limit, a PWM signal is deliveredfrom the MPU 14 to the DC motor driver 11 to rotate the DC motor in theseatbelt protracting direction at a step S2403, and it is determined ata step S2404 whether a predetermined time period t4 (e.g. 1 sec) haselapsed after the protraction of the seatbelt by the DC motor 10 wasstarted. When the predetermined time period t4 has elapsed, a properamount of looseness is given to the occupant.

[0276] If it is determined at the step S2404 that the predetermined timeperiod t4 has not elapsed, the processing returns to the step S2403,whereas if the predetermined time period t4 has elapsed, the protractionof the seatbelt by the DC motor 10 is stopped at a step S2405, followedby terminating the present processing.

[0277] Referring again to FIG. 21, it is determined at a step S2109whether protraction of the seatbelt has been made, based upon theterminal voltage across the DC motor 10. If protraction of the seatbelthas not been made, the same determination is repeated, whereas ifprotraction of the seatbelt has been made, it is determined at a stepS2110 whether the protraction of the seatbelt has been completed, bydetermining whether the terminal voltage across the DC motor 10 is equalto or less than a predetermined value (e.g. 0.3 volts). If theprotraction of the seatbelt has not been completed, the samedetermination is repeated, whereas if it has been completed, it isdetermined at a step S2111 whether the vehicle speed v exceeds apredetermined value v1 (e.g. 10 km/h), based upon an output signal fromthe vehicle speed sensor 42.

[0278] If the vehicle speed v does not exceed the predetermined valuev1, the same determination is repeated, whereas if the former exceedsthe latter, the processing returns to the step S2108 to again executethe seatbelt slackening control. By virtue of this control, when thevehicle is reversed at a slow speed for parking, for example, the reelshaft is not normally rotated, it can be prevented that the seatbelt isretracted to its limit while the occupant looks backward.

[0279] Referring back to FIG. 20, if it is determined at the step S2105that the signal received from the buckle connection detector 16 is theON signal, the MPU 14 judges that the buckle connection detector 16 hasthe ON fault, and then causes the warning device 38 to give warning at astep S2124.

[0280] Then, it is determined at a step S2125 whether a predeterminedtime period t5 (e.g. 10 sec) has elapsed. If the predetermined timeperiod t5 has not yet elapsed, the same determination is repeated,whereas if the predetermined time period t5 has elapsed, it isdetermined at a step S2126 whether the signal received from the windingamount detector 37 is still the OFF signal. If the signal from thewinding amount detector 37 has changed to the ON signal, the processingproceeds to the seatbelt storing control at a step S2132, whereas if thesignal from the winding amount detector 37 is still the OFF signal, itis regarded that the seatbelt has been attached to the occupant, andthen the processing proceeds to a step S2127 to execute seatbeltslackening control of FIG. 23.

[0281] Then, it is determined at a step S2128 whether the seatbelt hasbeen protracted by the occupant, from the terminal voltage across the DCmotor 10. If the seatbelt has been protracted by the occupant, it isdetermined at a step S2129 whether the protraction of the seatbelt hasbeen terminated, from the terminal voltage. If the protraction has beenterminated, the seatbelt slackening control is again executed at thestep S2127.

[0282] If it is determined at the step S2128 that the seatbelt has notbeen protracted by the occupant, the seatbelt is forcibly retractedevery predetermined time period t6 (e.g. 5 sec) so long as the signalreceived from the winding amount detector 37 is the OFF signal, and itis determined at a step S2131 whether the signal from the winding amountdetector 37 has changed from the OFF signal to the ON signal before theretraction of the seatbelt has reached its limit.

[0283] If the signal received from the winding amount detector 37remains to be the OFF signal, the processing returns to the step S2127,whereas if it has changed to the ON signal, it is regarded that theseatbelt has been released from the attached state, and then the MPU 14executes the seatbelt storing control at the step S2132.

[0284] As described above, according to the present embodiment, after itis regarded that the buckle connection detector 16 has the ON fault withthe seatbelt disconnected from the occupant, the MPU 14 executes theseatbelt slackening control if the signal received from the windingamount detector 37 is still the OFF signal. As a result, even in thecase where attachment or disconnection of the seatbelt cannot beaccurately detected due to the fault of the buckle connection detector16, a comfortable seatbelt attaching feeling can be given to theoccupant. On the other hand, after it is regarded that the buckleconnection detector 16 has ON fault, if the signal received from thewinding amount detector 37 has changed from the OFF signal to the ONsignal, the seatbelt storing control is executed. As a result, it can beprevented that the seatbelt is caught in the door.

[0285]FIG. 24 shows an example of the waveforms of signals input to theMPU 14 when “ON fault” occurs after the seatbelt shifts from a stateattached to the occupant to a state disconnected from the occupant.FIGS. 25 and 26 are flowcharts showing a control program executed by theMPU 14.

[0286] First, the counter n is set to 0 and the seatbelt storage flag isreset at a step S2600, and it is determined at a step S2601 whether thesignal received from the buckle connection detector 16 is the ON signal.The step S2601 and steps S2602 to S2618 are identical with the stepsS2106 to S2123 of FIG. 21 described above, description of which isomitted.

[0287] After the execution of the step S2610, after the answer to thequestion of the step S2616 is YES, or after the execution of the stepS2615 or S2618, when the seatbelt has shifted from the attached state tothe disconnected state, it is determined at a step S2619 whether thesignal received from the buckle connection detector 16 has changed fromthe ON signal to the OFF signal. If the signal from the buckleconnection detector 16 remains to be the ON signal, the processingreturns to the step S2601, whereas if the signal from the buckleconnection detector 16 has changed from the ON signal to the OFF signal,the seatbelt storing control of FIG. 18 is started at a step S2620.

[0288] Then, during the execution of the seatbelt storing control, it isdetermined at a step S2621 whether the signal received from the buckleconnection detector 16 has changed from the OFF signal to the ON signal.If there has been no change in the signal, the processing proceeds to astep S2625, hereinafter referred to, whereas if the signal has changedfrom the OFF signal to the ON signal, it is regarded that the seatbelthas shifted from the disconnected state to the attached state, and thenthe seatbelt slackening control of FIG. 23 is started at a step S2622.

[0289] While the seatbelt is retracted during the execution of theseatbelt slackening control, it is determined at a step S2623 whetherthe signal from the winding amount detector 37 has changed to the ONsignal. If the signal has not changed to the ON signal, the processingreturns to the step S2622, whereas if it has changed to the ON signal,the MPU 14 regards that the buckle connection detector 16 has ON fault,then causes the warning device 38 to give warning at a step S2624, andagain executes the seatbelt storing control at a step S2625, followed bythe processing returning to the step S2601.

[0290] As described above, according to the present embodiment, afterthe seatbelt shifted from the attached state to the disconnected stateand then the MPU 14 regards that the buckle connection detector 16 hasON fault, the seatbelt storing control is executed. As a result, it canbe prevented that the seatbelt is caught in the door.

[0291] Now, description will be made of processing executed by the MPU14 in the event that the buckle connection detector 16 continuesdelivering the OFF signal even when the seatbelt is in a state attachedto the buckle (hereinafter referred to as “OFF fault”).

[0292]FIG. 27 is a view showing an example of the waveforms of signalsinput to the MPU 14 when “OFF fault” occurs with the seatbeltdisconnected from the occupant. FIG. 28 is a flowchart showing a controlprogram executed by the MPU 14.

[0293] The present control program is started when the ON signal fromthe winding amount detector 37 and at the same time the OFF signal fromthe buckle connection detector 16 are received by the MPU 14.

[0294] First, the counter n is set to 0 and the seatbelt storage flag isreset at a step S2901, and it is determined at a step S2902 whether theseatbelt is being protracted, from the terminal voltage across the DCmotor 10. If the seatbelt is not being protracted, the samedetermination is repeated, whereas if the seatbelt is being protracted,it is determined at a step S2903 whether the signal received from thewinding amount detector 37 has changed from the ON signal to the OFFsignal. If there has been no change in the signal, it is determined at astep S2904 whether the protraction of the seatbelt has been terminated,from the terminal voltage across the DC motor 10.

[0295] If the protraction of the seatbelt has not been terminated, theprocessing returns to the step S2903, whereas if the protraction hasbeen terminated, the processing proceeds to a step S2911 to execute theseatbelt storing control, described hereinafter.

[0296] If it is determined at the step S2903 that the signal from thewinding amount detector 37 has changed from the ON signal to the OFFsignal, it is determined at a step S2905 whether a predetermined timeperiod t7 (e.g. 10 sec) has elapsed while the OFF signal continues to bereceived from the winding amount detector 37.

[0297] If the predetermined time period t7 has not yet elapsed, the samedetermination is repeated, whereas if it has elapsed, it is determinedat a step S2906 whether the signal from the buckle connection detector16 is the OFF signal.

[0298] If the signal from the buckle connection detector 16 is the ONsignal, the processing proceeds to the step S2106 of FIG. 21, whereas ifthe signal is the OFF signal, the MPU 14 regards that the buckleconnection detector 16 has OFF fault, causes the warning device 38 togive warning at a step S2907, and executes the seatbelt slackeningcontrol of FIG. 23 at a step S2908.

[0299] So long as the signal received from the winding amount detector37 is the OFF signal, the seatbelt is forcibly retracted everypredetermined time period t8 (e. g. 5 sec) at a step S2909, and it isdetermined at a step S2910 whether the signal from the winding amountdetector 37 has changed from the OFF signal to the ON signal before theretraction of the seatbelt reaches its limit. If the signal has notchanged from the OFF signal to the ON signal, the same determination isrepeated, whereas if the signal has changed to the ON signal, the MPU 14regards that the seatbelt has been released from the attached state, andthen executes the seatbelt storing control of FIG. 18 at the step S2911,followed by the processing returning to the step S2902.

[0300] As described above, according to the present embodiment, after itis regarded that the buckle connection detector 16 has the OFF faultwith the seatbelt disconnected from the occupant, the MPU 14 executesthe seatbelt slackening control. As a result, even in the case whereattachment or disconnection of the seatbelt cannot be accuratelydetected due to the fault of the buckle connection detector 16, acomfortable seatbelt attaching feeling can be given to the occupant. Onthe other hand, after it is regarded that the buckle connection detector16 has OFF fault, if the signal received from the winding amountdetector 37 has changed from the OFF signal to the ON signal, theseatbelt storing control is executed. As a result, it can be preventedthat the seatbelt is caught in the door.

[0301]FIG. 29 shows an example of the waveforms of signals input to theMPU 14 when “OFF fault” occurs after the seatbelt shifts from a stateattached to the occupant to a state disconnected from the occupant. FIG.30 is a flowchart showing a control program executed by the MPU 14.

[0302] The present control program is interrupt processing triggered atregular time intervals and started when the OFF signal from the windingamount detector 37 and at the same time the ON signal from the buckleconnection detector 16 are received by the MPU 14.

[0303] First, it is determined at a step S3101 whether the signalreceived from the buckle connection detector 16 has changed from the ONsignal to the OFF signal. If the signal has not changed from the ONsignal to the OFF signal, the present processing is immediatelyterminated, whereas if the signal has changed from the ON signal to theOFF signal, the MPU 14 regards that the seatbelt has shifted from theattached state to the disconnected state, and then executes the seatbeltstoring control of FIG. 18 at a step S3102.

[0304] Then, it is determined at a step S3103 whether the signal fromthe winding amount detector 37 has changed from the OFF signal to the ONsignal before completion of storing of the seatbelt. If the signal haschanged from the OFF signal to the ON signal, the present processing isterminated, whereas if there has been no change in the signal, that is,the signal from the winding amount detector 37 is still the OFF signaleven when the storing of the seatbelt is just about to be completed, theMPU 14 regards that the buckle connection detector 16 has OFF fault,then causes the warning device 38 to give warning at a step S3104, andexecutes the seatbelt slackening control of FIG. 23 at a step S3105,supposing that the seatbelt is in the attached state.

[0305] Then, it is determined at a step S3106 whether the seatbelt hasbeen protracted by the occupant, from the terminal voltage across the DCmotor 10. If the seatbelt has been protracted by the occupant, it isdetermined at a step S3107 whether the protraction of the seatbelt hasbeen terminated, from the terminal voltage across the DC motor 10. Ifthe protraction of the seatbelt has been terminated, the seatbeltslackening control is again executed at the step S3105.

[0306] If it is determined at the step S3106 that no protraction of theseatbelt has been made by the occupant, so long as the signal receivedfrom the winding amount detector 37 is the OFF signal, the seatbelt isforcibly retracted every predetermined time period t9 (e.g. 5 sec) at astep S3108, and it is determined at a step S3109 whether the signal fromthe winding amount detector 37 has changed from the OFF signal to the ONsignal before the retraction of the seatbelt reaches its limit.

[0307] If there has been no change in the signal, the processing returnsto the step S3105, whereas if a change has been made from the OFF signalto the ON signal, the present processing is terminated.

[0308] As described above, according to the present embodiment, afterthe seatbelt has shifted from the attached state to the disconnectedstate and then it is determined that the buckle connection detector 16has OFF fault, the seatbelt slackening control is carried out. As aresult, even in the case where attachment or disconnection of theseatbelt cannot be accurately detected due to the fault of the buckleconnection detector 16, a comfortable seatbelt attaching feeling can begiven to the occupant.

[0309] Although in the present embodiment the winding amount detector 37detects the thickness of the seatbelt wound on the reel shaft 3 as thewinding amount of the seatbelt, the terminal voltage across the DC motor10 or the current flowing to the DC motor 10 may alternatively bedetected to determine the winding amount. That is, when the DC motor 10is not driven, voltage is developed between terminals of the DC motor 10due to an electromotive force thereof, and the voltage is detected andaccumulated, to determine the amount of retraction or protraction of theseatbelt from the resulting cumulative value. When the DC motor 10 isdriven, the reel shaft 3 rotates such that current flowing to the DCmotor 10 varies. Therefore, the time is accumulated so long as thecurrent varies, and the accumulated time is used to determine the amountof retraction or protraction of the seatbelt.

[0310] Although in the above described embodiment the control executedby the MPU 14 is carried out irrespective of the traveling speed of theautomotive vehicle, preferably the seatbelt slackening control may becarried out when the traveling speed is higher than a predeterminedvalue and the seatbelt storing control when the traveling speed is lowerthan a predetermined value.

[0311] Seventh Embodiment

[0312] An automotive passenger restraint and protection apparatusaccording to a seventh embodiment of the invention includes an electricretractor 700, which is distinguished from the electric retractor 100 ofFIG. 1 in that a detecting circuit 45 is provided in place of thetemperature sensor 19.

[0313] The detecting circuit 45 is connected to the DC motor driver 11,the MPU 14, and the buckle connection detector 16, and delivers a modecontrol signal for selecting a reduced power consumption mode or anormal power consumption mode, based upon a voltage signal generated byprotraction of the seatbelt by the occupant or a voltage signal from thebuckle connection detector 16. Except for the above, the construction ofthe electric retractor 700 is identical with that of the electricretractor 100, illustration and description of which are thereforeomitted.

[0314]FIG. 31 is a circuit diagram showing the arrangements of the DCmotor driver 11, the detecting circuit 45 and the buckle connectiondetector 16 according to the seventh embodiment. In FIG. 31, referencenumeral P7 designates an input terminal for receiving a control signaldelivered to the detecting circuit 45 from the MPU 14, and referencenumeral P8 designates an output terminal for outputting the mode controlsignal for selecting the reduced power consumption mode or the normalpower consumption mode, to the MPU 14. The reduced power consumptionmode is a mode for stopping all the functions of the MPU 14 except for afunction of receiving the mode control signal, and the normal powerconsumption mode is a mode for allowing all the functions of the MPU 14to operate.

[0315] The detecting circuit 45 includes a NAND circuit which has oneinput terminal thereof serving as the input terminal P7, and the otherinput terminal connected to an output terminal of an OR circuit 46. Anoutput terminal of the NAND circuit serves as the output terminal P8.The OR circuit 46 has one input terminal thereof connected between thecapacitor C3 of the IF IF4 and the output terminal P6 at a junction Q1,and the other input terminal connected to an output terminal of a NOTcircuit 47, which in turn has an input terminal thereof connected to thebattery Vb through a resistance 49, as well as to ground via a switch 48which closes when the tongue of the seatbelt is attached to the buckle.The input terminal of the NOT circuit 47 is connected to a junctionbetween voltage dividing resistances 49 and 50 serially connectedbetween the battery Vb and ground. The switch 48 and the resistances 49,50 are components of the buckle connection detector 16.

[0316] The OR circuit 46 receives a high-level (H) signal from thejunction Q1 when the seatbelt is protracted by the occupant. The switch48 closes when the tongue of the seatbelt is connected to the buckle bythe occupant, and then the NOT circuit 47 delivers a high-level (H)signal to the OR circuit 46. When no protraction of the seatbelt is madeby the occupant and when the seatbelt tongue is not connected to thebuckle, a low-level (L) signal is input to the OR circuit 46.

[0317]FIGS. 32A to 32D show changes in an output signal (mode controlsignal) delivered from the output terminal P8 to the MPU 14 and modes ofthe MPU 14 corresponding to the changes.

[0318] First, as shown in FIG. 32A, when the output signal from theoutput terminal P8 turns from a high level H to a low level L, the MPU14 enters the normal power consumption mode. As shown in FIG. 32B, whenthe mode control signal from the output terminal P8 turns from the lowlevel L to the high level H the MPU 14 enters the reduced powerconsumption mode. When the mode control signal remains at the low levelL (FIG. 32C) or when the mode control signal remains at the high level L(FIG. 32D), the MPU 14 remains in the same mode without a change in themode.

[0319]FIG. 33 is a flowchart showing reduced power consumption controlexecuted by the MPU 14. This control forms part of main control executedby the MPU 14 and is executed when the storage of the seatbelt has beencompleted.

[0320] In an initial state, the MPU 14 sets itself into the normal powerconsumption mode at a step S3401. Then, it is determined at a step S3402whether attaching of the seatbelt tongue to the buckle has been detectedby the buckle connection detector 16. If attaching of the seatbelttongue to the buckle has not been detected, the present processing isimmediately terminated, whereas if attaching of the seatbelt tongue hasbeen detected, it is determined at a step S3403 whether a predeterminedtime period t (e.g. 3 sec) has elapsed, from the value of the timer 15.If the predetermined time period t has not yet elapsed, the samedetermination is repeated, whereas if the predetermined time period thas elapsed, the MPU 14 delivers a high-level (H) control signal to thedetecting circuit 45 through the input terminal P7 at a step S3404, andthe power consumption mode is set to the reduced power consumption modeat a step S3405.

[0321] Then, it is determined at a step S3406 whether the mode controlsignal from the detecting circuit 45 has turned to the low level (L). Onthis occasion, the mode control signal goes low if the high-level (H)signal indicative of protraction of the seatbelt by the occupant or thehigh-level (H) signal indicative of attaching of the seatbelt tongue tothe buckle is delivered through the OR circuit 46 to the detectingcircuit 45. If the mode control signal has not turned to the low level(L), the same determination is repeated, whereas if the mode controlsignal has turned to the low level (L), the power consumption mode isset to the normal power consumption mode at a step S3407. Then, alow-level (L) control signal is delivered to the detecting circuit 45through the input terminal P7 at a step S3408, followed by terminatingthe present processing.

[0322] As described above, according to the present embodiment, upon thelapse of the predetermined time period t after disconnection of theseatbelt from the occupant is detected while the MPU 14 is in the normalpower consumption mode, the power consumption mode is set to the reducedpower consumption mode whereby all the functions of the MPU 14 arestopped except for the function of receiving the mode control signal.Thereafter, when protraction of the seatbelt by the occupant orattaching of the seatbelt tongue to the buckle is detected, the powerconsumption mode is set to the normal power consumption mode whereby allthe functions of the MPU 14 can be resumed. Thus, it is possible tochange the operative state of the MPU 14 according to the expectedability thereof to thereby reduce the power consumption.

[0323] Eighth Embodiment

[0324]FIG. 34 shows the arrangement of an electric retractor 800provided in an automotive passenger restraint and protection apparatusaccording to an eighth embodiment of the invention.

[0325] In FIG. 34, the DC motor driver 11 is connected to a power source63 which supplies the DC motor driver 11 with supply power required fordriving the DC motor 10. The electric retractor 800 includes adriving/traveling state detector 55 for detecting states of driving andtraveling of the automotive vehicle by the occupant, which is comprisedof an MPU 54 which is connected to the MPU 14, a distance sensor 52, asteering angle sensor 53, and a DC-DC converter 56.

[0326] The MPU 14 is connected to the power source 63 through a DC-DCconverter 64 which converts supply voltage from the power source 63 to alevel suitable for operation of the MPU 14, e.g. 5 volts. A transistor58 has a base thereof connected through a resistance 57 to the MPU 14.The transistor 58 has an emitter thereof grounded and a collectorthereof connected through a resistance 59 to a coil 61 of a relaycircuit 60. The coil 61 is connected to the power source 63, which isconnected through contacts 62 of the relay circuit 60 to the DC-DCconverter 56 which converts supply voltage from the power source 63 to alevel suitable for operation of the MPU 14 as well as the distancesensor 52 and the steering angle sensor 53, e.g. 5 volts. The DC-DCconverter 56 is connected to the MPU 54 as well as the distance sensor52 and steering angle sensor 53 which are connected to the MPU 54.

[0327] The distance sensor 52 detects the distance between the presentvehicle (occupant's vehicle) and an object lying ahead of the vehicle,and the steering angle sensor 53 senses the steering angle of a steeringarm of the vehicle.

[0328] The MPU 14 determines whether protraction of the seatbelt hasbeen made, from the sign of terminal voltage across the DC motor 10, andalso determines whether retraction of the seatbelt has been completed,from the current i flowing to the DC motor 10.

[0329] Next, the flow of control signals at various components of theautomotive passenger restraint and protection apparatus according to thepresent embodiment will be described.

[0330] The distance sensor 52 delivers an output signal indicative ofresults of detection of the distance between the present vehicle and anobject lying ahead of the vehicle to the MPU 54. The MPU 54 calculates asafety distance ds (m) between the present vehicle and an object lyingahead by the use of the following formula (1), and when the calculatedsafety distance ds is larger than a value indicated by the output signalfrom the distance sensor 52, the MPU 54 delivers an output signal forcollision danger warning to the MPU 14. Further, the MPU 54 calculates acollision unavoidable distance dd (m) by the use of the followingformula (2), and when the calculated collision unavoidable distance ddis larger than a value indicated by the output signal from the distancesensor 52, the MPU 54 delivers an output signal indicative of acollision being unavoidable, to the MPU 14.

ds=Vr×(td+β)  (1)

dd=Vr×td  (2)

[0331] where Vr represents relative speed (m/sec), td response delay ofthe driver (e.g. 0.5 to 2 sec), and β a value determined by the brakingcharacteristic of the vehicle (e.g. 0.5 to 2 sec).

[0332] The steering angle sensor 53 delivers an output signal indicativeof the sensed steering angle to the MPU 54, and when the maximum valueof change amount in the detected steering angle within a prescribed timeperiod (e.g. 2 sec) is less than a predetermined value (e.g. 8 degrees),the MPU 15 judges that the driver might be dozing and delivers an outputsignal for doze warning to the MPU 14.

[0333] The buckle connection detector 16 detects whether the tongue ofthe seatbelt has been connected to the buckle, and delivers an outputsignal indicative of results of the detection to the MPU 14. The DCmotor driver 11 controls the rotation of the DC motor 10, based upon acontrol signal from the MPU 14.

[0334] The MPU 14 operates in response to the signal from the buckleconnection detector 16, indicating that the seatbelt tongue has beenconnected to the buckle, to deliver a high-level signal to thetransistor 58 through the resistance 57, whereby the transistor 58 isturned on to permit current to flow from the power source 63 to the coil61 to close the contacts 62, and permit supply voltage to be supplied tothe MPU 54 as well as to the distance sensor 52 and the steering anglesensor 53. On the other hand, when the signal from the buckle connectiondetector 16, indicating that the seatbelt tongue has been connected tothe buckle has ceased to be delivered to the MPU 14, the MPU 14 deliversa low-level signal to the transistor 58, whereby the transistor 58 isturned off to stop supply of current from the power source 63 to thecoil 61 to open the contacts 62 and stop supply of the supply voltage tothe MPU 54 as well as to the distance sensor 52 and the steering anglesensor 53.

[0335] As described above, according to the present embodiment, it iscontrolled such that when the seatbelt is in the attached state, supplyvoltage from the power source is supplied to the MPU 54 nor to thedistance sensor 52 and the steering angle sensor 53, while when theseatbelt is in the disconnected state, supply voltage from the powersource is not supplied to the MPU 54 nor to the distance sensor 52 andthe steering angle sensor 53. Thus, only when it is necessary to operatethese components, the supply voltage can be supplied, thereby reducingthe power consumption.

[0336] Although in the present embodiment the control of supply voltageto the MPU 54, etc. is made depending upon whether the seatbelt is inthe attached state or in the disconnected state, this is not limitative.For example, alternatively the control of supply voltage to the MPU 54and its peripheral components may be carried out depending upon a shiftposition of a transmission of the automotive vehicle, providingsubstantially the same results. More specifically, a shift positionsensor may be connected to the MPU 14, and if the detected shiftposition is the parking position, the supply of power to the MPU 54 andits peripheral components is inhibited, while if the detected shiftposition is other than the parking position, the supply of the MPU 14,etc. is permitted. Further, the control of supply voltage to the MPU 54and its peripheral components may be carried out depending upon whethera parking brake of the automotive vehicle is pulled up or in operativeposition, providing substantially the same results. More specifically, aparking brake position sensor may be connected to the MPU 14, and if thedetected parking brake position is the pulled-up or operative position,the supply of power to the MPU 54 and its peripheral components isinhibited, while if the detected parking brake position is other thanthe pulled-up or operative position, the supply of the MPU 14, etc. ispermitted.

[0337] Ninth Embodiment

[0338] An electric retractor provided in an automotive passengerrestraint and protection apparatus according to a ninth embodiment ofthe invention is identical in construction with the electric retractor100, illustration and description of which are therefore omitted.

[0339]FIG. 35 is a flowchart showing seatbelt storing control accordingto the ninth embodiment, executed by the MPU 14 in retracting theseatbelt.

[0340] First, it is determined at a step S3601 whether disconnection ofthe seatbelt tongue from the buckle has been detected by the buckleconnection detector 16. If disconnection of the seatbelt tongue has notbeen detected, the present processing is immediately terminated, whereasif disconnection of the seatbelt tongue has been detected, a controlsignal is delivered to the DC motor driver 11 to rotate the reel shaft 3in the seatbelt retracting direction at a step S3602, whereby theseatbelt is retracted. On this occasion, the timer 15 measures timeelapsed after the start of delivery of the control signal to the DCmotor driver 11.

[0341] Then, it is determined at a step S3603 whether a predeterminedtime period (e.g. 3 sec) has elapsed after the start of delivery of thecontrol signal to the DC motor driver 11. Upon the lapse of thepredetermined time period, a control signal is delivered to the DC motordriver 11 to stop the rotation of the reel shaft 3 at a step S3504,whereby the rotation of the reel shaft 3 is stopped. On this occasion,it is assumed that locking of the seatbelt by the seatbelt lockingmechanism 2 does not take place. On this occasion, the timer 15 measurestime elapsed after the delivery of the control signal to the DC motordriver 11 to stop the rotation of the reel shaft 3.

[0342] Then, it is determined at a step S3605 whether protraction of theseatbelt has been made. If protraction of the seatbelt has been made,seatbelt protraction control is executed, as described hereinafter. Ifprotraction of the seatbelt has not been made, it is determined at astep S3606 whether a predetermined time period (e.g. 10 sec) has elapsedafter the delivery of the control signal to the DC motor driver 11 tostop the rotation of the reel shaft 3. If the predetermined time periodhas not yet elapsed, the processing returns to the step S3605, whereasif it has elapsed, a control signal is delivered to the DC motor driver11 to rotate the reel shaft 3 in the seatbelt retracting direction at astep S3607, whereby the seatbelt is retracted.

[0343] Then, it is determined at a step S3608 whether the retraction ofthe seatbelt has been completed. If the completion of the retraction hasbeen completed, a control signal is delivered to the DC motor driver 11to stop the rotation of the reel shaft 3 at a step S3609, and then theseatbelt protraction control is executed, as described hereinafter, at astep S3610, followed by terminating the present processing.

[0344]FIG. 36 is a flowchart showing seatbelt protraction controlaccording to the ninth embodiment, executed by the MPU 14 in protractingthe seatbelt.

[0345] First, it is determined at a step S3701 whether attaching of theseatbelt tongue to the buckle has been detected by the seatbeltconnection detector 16. If attaching of the seatbelt tongue to thebuckle has been detected, it is regarded that the protraction of theseatbelt has been completed, and a control signal is delivered to the DCmotor driver 11 to stop the rotation of the reel shaft 3 at a stepS3708, followed by terminating the present processing. On the otherhand, if attaching of the seatbelt tongue to the buckle has not beendetected, a control signal is delivered to the DC motor driver 11 tostop the rotation of the reel shaft 3 so as to execute assisting of theprotraction of the seatbelt at a step S3702.

[0346] Then, the terminal voltage across the DC motor 10 and the signthereof are measured by the circuit C2 of the DC motor driver 11 at astep S3703. It is determined whether the measured terminal voltageexceeds a predetermined value (e.g. 0.3 volts) and at the same time thesign of the terminal voltage corresponds to the direction of protractingthe seatbelt at a step S3704. The answer to this question becomesaffirmative (YES) if the occupant lightly protracts the seatbelt.

[0347] If it is determined at the step S3704 that the terminal voltagedoes not exceed the predetermined value (0.3 volts) or the sign does notcorrespond to the direction of protracting the seatbelt, the processingreturns to the step S3703, whereas if the terminal voltage exceeds thepredetermined value (0.3 volts) and at the same time the sign of theterminal voltage corresponds to the direction of protracting theseatbelt, the MPU 14 delivers a control signal commanding to rotate thereel shaft 3 in the seatbelt protracting direction, to the DC motordriver 11 at a step S3705, whereby the seatbelt can be easilyprotracted.

[0348] According to the control of the steps S3701 to S3705 describedabove, when the measured terminal voltage exceeds the predeterminedvalue (0.3 volts) and at the same time the sign of the terminal voltagecorresponds to the direction of protracting the seatbelt, the seatbeltcan be brought into a state where it can be easily protracted. As aresult, a large force as required in the conventional apparatus is notneeded, and therefore even a weak occupant who has degraded physicalability such as an advanced-age occupant can easily mount the seatbeltonto his body.

[0349] Then, it is determined at a step S3706 whether attaching of thetongue of the seatbelt has been detected by the buckle connectiondetector 16. If attaching of the seatbelt has been detected, theprocessing proceeds to the step S3708. On the other hand, if attachingof the seatbelt has not been detected, it is determined at a step S3707whether a predetermined time period (e.g. 7 sec) has elapsed after thecontrol signal commanding to rotate the reel shaft 3 was delivered tothe DC motor driver 11.

[0350] If the predetermined time period has not elapsed, the processingreturns to the step S3705, whereas if it has elapsed, which means thatthe seatbelt has been protracted but the tongue of the seatbelt has notbeen connected to the buckle such that the seatbelt is in a slackenedstate, a control signal commanding to stop the rotation of the reelshaft 3 is delivered to the DC motor driver 11 at a step S3708, followedby terminating the present processing.

[0351] As described above, according to the present embodiment, whendisconnection of the seatbelt tongue from the buckle has been detected,retraction of the seatbelt is started. Then, before completion of theretraction, the retraction of the seatbelt is stopped by stopping therotation of the reel shaft 3 for a predetermined time period. If theseatbelt is protracted during the predetermined time period, theseatbelt protraction control is executed, whereas if the seatbelt is notprotracted over the predetermined time period, retraction of theseatbelt is carried out. Therefore, in the case where if the seatbelttongue is once disconnected from the buckle and soon then the seatbelttongue is connected to the buckle, it is not necessary to protract orpull the seatbelt against the retracting force of the electricretractor, as is distinct from the conventional automotive passengerrestraint and protection apparatus, to thereby facilitate mounting ofthe seatbelt onto the occupant.

[0352] Although in the present embodiment the retraction of the seatbeltis stopped only one time over the predetermined time period beforecompletion of the retraction (steps S3604 to S3606), the stopping of theretraction may be made a plurality of times.

[0353] Tenth Embodiment

[0354]FIG. 37 shows the arrangement of an automotive passenger restraintand protection apparatus according to a tenth embodiment of theinvention. The automotive passenger restraint and protection apparatusaccording to the present embodiment is comprised of a collision dangerpredictor 66, a speed detector 67, a controller 68, a driver 69, and aretractor main body 70.

[0355] The collision danger predictor 66 is adapted to generate acollision unavoidableness signal indicating that a degree of danger ofcollision of the automotive vehicle with an obstacle lying ahead hasreached such a degree that the collision cannot be avoided only throughoperation of the driver, and a collision danger signal indicating that adanger of collision is impending but the collision can be avoidedthrough operation of the driver. The speed detector 67 generates asignal indicative of the traveling speed of the automotive vehicle.

[0356] The controller 68 controls the driver 69, based upon the signalsfrom the collision danger predictor 66 and the speed sensor 67. Thedriver 69 drives the retractor main body 70 which carries out retractionand protraction of the seatbelt.

[0357]FIG. 38 shows details of the arrangement of the automotivepassenger restraint and protection apparatus according to the tenthembodiment. The collision danger predictor 66 is comprised of a relativedistance sensor 71, a doze sensor 72, an interface (I/F) 73, and amicrocomputer unit (MCU) 74. The relative distance sensor 71 is adaptedto generate a voltage signal corresponding to the distance between anobstacle and the present automotive vehicle. The doze sensor 72 isadapted to detect a change in the steering angle sensed by a steeringangle sensor provided in a steering of the automotive vehicle andgenerate a signal indicative of a doze of the driver if the change inthe steering angle exceeds a predetermined value, for example.

[0358] The speed detector 67 is formed of a speed sensor 75 andgenerates and delivers a signal indicative of the sensed traveling speedV of the vehicle to the MPU 74 via the interface 73.

[0359] The controller 68 is mainly comprised of the MCU 74, to which areconnected via the interface 73 the relative distance sensor 71, the dozesensor 72 and the speed sensor 75. The MCU 74 stores in an internalmemory thereof the traveling speed V of the vehicle sensed by the speedsensor 75 and produces the collision danger signal and the collisionunavoidableness signal based upon output signals from the relativedistance sensor 71 and the doze sensor 72 and delivers these signals toswitches SW1, SW2, and SW3.

[0360] The driver 69 is comprised of a motor 78, the switches SW1, SW2,and SW3, a DC power source 76, and an oscillator 77. When the collisiondanger signal is received from the MCU 74, the driver 69 operates inresponse to the collision danger signal to close the switch SW1 and atsame time cause movable contacts of the switches SW2 and SW3 to beconnected to respective fixed contacts A, whereby an output signal fromthe oscillator 77 is delivered to the motor 78. The oscillator 77 has anoscillation frequency of 20 Hz in the present embodiment.

[0361] When the collision unavoidableness signal is received from theMCU 74, the driver 69 operates in response to the collisionunavoidableness signal to close the switch SW1 and at the same timecauses the movable contacts of the switches SW2 and SW3 to be connectedto respective fixed contacts B, whereby output voltage from the DC powersource 76 is applied to the motor 78.

[0362]FIGS. 39A and 39B schematically show the construction of aseatbelt device with the electric retractor according to the presentembodiment. In the seatbelt device, a seatbelt 79 with one end thereoffixed to a stationary shaft 80 extends through a buckle 81, a shoulderportion 82 and is wound on the retractor main body 70. When the motor78, which is directly coupled to the retractor main body 70, is driven,retraction or protraction of the seatbelt 79 is carried out while thetension of the seatbelt 79 is increased or decreased.

[0363]FIG. 40 is a flowchart showing a manner of operation of theautomotive passenger restraint and protection apparatus according to thepresent embodiment.

[0364] This processing is executed at predetermined time intervalsduring a time period of seatbelt attaching as electric retractorcontrol. First, it is determined at a step S4101 whether a collision ofthe vehicle with an obstacle lying ahead is unavoidable. If thecollision is not unavoidable, it is determined at a step S4102 whetherthere is a danger or possibility of a collision of the vehicle with anobstacle lying ahead. More specifically, these determinations arecarried out in the following manner:

[0365] That is, a relative distance Ad between the vehicle and theobstacle is detected by the relative distance sensor 71. Based upon thedetected relative distance Δd, a relative speed ΔV between the obstacleand the vehicle (=Δdi−Δdi−1) is calculated. Based upon the calculatedrelative speed ΔV, a time period t before the expected collision(=Δd/ΔV) is estimated.

[0366] It is determined whether the time period t before the expectedcollision exceeds a predetermined time period t1, that is, whether thereis a possibility of collision. If the time period t before the expectedcollision is shorter than the predetermined time period t1, it isdetermined whether the time period t before the expected collision isequal to or longer than a predetermined time period t2 which is shorterthan the predetermined time period t1. If the time period t is shorterthan the predetermined time period t2, it is judged that a collision ofthe vehicle with the obstacle lying ahead cannot be avoided only throughoperation of the driver, and then the MPU 74 generates the collisionunavoidableness signal. On the other hand, if the time period t is equalto or longer than the predetermined time period t2, the MPU 74 generatesthe collision danger signal.

[0367] Further, on the other hand, if the time period t before theexpected collision is equal to or longer than the predetermined timeperiod t1, it is determined whether a signal has been generated from thedoze sensor 72, which indicates that the driver is dozing, and if thesignal has been generated, the MPU 74 generates the collision dangersignal. On the other hand, if the signal has not been generated, it isregarded that there is no possibility of collision, and then the MCU 74does not generate the collision danger signal.

[0368] If it is determined at the step S4101 that a collision of thevehicle with an obstacle lying ahead is unavoidable, the MCU 74 deliversthe collision unavoidableness signal to the switches SW1, SW2, and SW3to close the switch SW1 and cause the movable contacts of the switchesSW2 and SW3 to be connected to the respective fixed contacts B, wherebyoutput voltage from the DC power source 76 is applied to the motor 78 todrive the same to start retraction of the seatbelt 79 at a step S4103.Then, the lapse of a predetermined time period is waited at a stepS4104. Upon the lapse of the predetermined time period, the retractionis stopped at a step S4105, followed by terminating the processing. Thispredetermined value is set to a time period within which the tension ofthe seatbelt 79 can be increased by the driving of the motor 78 toproperly fasten or restrain the occupant.

[0369] On the other hand, if it is determined at the step S4102 thatthere is a danger of a collision of the vehicle with an obstacle lyingahead, the MPU 74 delivers the collision danger signal to the switchesSW1, SW2, and SW3 to close the switch SW1 and cause the movable contactsof the switches SW2 and SW3 to be connected to the respective fixedcontacts A, whereby an output signal (frequency: 20 Hz) from theoscillator 77 is supplied to the motor 78 to drive the same to causealternate retraction and protraction of the seatbelt 79 onto or from theretractor main body 70 to periodically increase and decrease or generatevibration by applying pressure to and release the same from the occupantat a step S4106. Then, the traveling speed V1 of the present vehiclesensed by the speed sensor 75 is stored in the internal memory of theMCU 74 at a step S4107, followed by terminating the present processing.

[0370] On the other hand, if it is determined at the step S4102 thatthere is no danger of collision and hence the collision danger signal isnot generated, it is determined at a step S4108 whether a difference ΔVbetween the traveling speed V1 of the present vehicle stored at the stepS4107 and a current traveling speed V2 of the present vehicle exceeds apredetermined value. The predetermined value is set to such a value thatthe vehicle has been sufficiently decelerated after the collision dangersignal ceased to be generated and the vehicle cannot be expected toenter a dangerous state.

[0371] If it is determined that the speed difference ΔV exceeds thepredetermined value, it is judged that a dangerous state has been fullyobviated, and then the MCU 74 delivers a signal to the switch SW1 toopen the same to thereby deenergize the motor 78 to stop the vibrationof the seatbelt at a step S4109. On the other hand, if the speeddifference ΔV does not exceed the predetermined value, it is judged thata dangerous state has not yet been fully obviated, and then the MCU74keeps the switch SW1 closed and the movable contacts of the switches SW2and SW3 connected to the respective fixed contacts A, followed byterminating the processing.

[0372] As described above, according to the present embodiment, when itis determined that there is no danger of a collision of the vehicle withan obstacle to stop generation of the collision danger signal, it isdetermined whether the speed difference ΔV between the stored travelingspeed V1 of the vehicle and the current traveling speed V2 of thevehicle exceeds a predetermined value, and if the former does not exceedthe latter, it is judged that a dangerous state has not been fullyobviated, and then the processing is terminated without stoppingvibration of the seatbelt. As a result, so long as it can be expectedthat the vehicle enters a dangerous state even after the collisiondanger signal ceases to be generated, vibration is continued byalternately applying pressure and release the same to and from theoccupant to thereby fully alert the occupant to the danger. Thus, theautomotive passenger restraint and protection apparatus can beeffectively utilized as a warning device.

[0373] Although in the present embodiment the switches SW1 to SW3 areswitched by signals from the MCU 74 to selectively deliver supplyvoltage from the DC power source 76 or the output from the oscillator 77to the motor 78, this is not limitative, but, for example, an interfacecircuit for detecting terminal voltage across the motor or supplycurrent to the motor and a motor driving circuit may be provided suchthat the MCU 14 detects the terminal voltage or the supply current andcontrols the motor driving circuit based upon the detected terminalvoltage or supply current to thereby drive the motor 78 for retractionand protraction of the seatbelt.

[0374] Eleventh Embodiment

[0375] An automotive passenger restraint and protection apparatusaccording to an eleventh embodiment of the invention includes anelectric retractor 1100, which is distinguished from the electricretractor 100 of FIG. 1 in that an A/D converter 83 is included in theMPU 14, for sampling voltage signals every predetermined time period.Except for this, the construction of the electric retractor 1100 isidentical with that of the electric retractor 100, illustration anddescription of which are therefore omitted.

[0376] The MPU 14 receives voltage signals from the IFs IF3 and IF4 inFIG. 2 and measures terminal voltage across the DC motor 10, based uponthe received voltage signals. FIG. 41A shows an example of the waveformof terminal voltage across the DC motor 10 containing pulsatingcomponents assumed when the seatbelt is slowly protracted by theoccupant, and FIG. 41B shows an example of the waveform of terminalvoltage across the DC motor 10 containing pulsating components assumedwhen the seatbelt is quickly protracted by the occupant.

[0377]FIG. 42 is a flowchart showing a control program according to theeleventh embodiment, executed by the MPU 14.

[0378] First, it is determined at a step S4301 whether attaching of theseatbelt tongue to the buckle has been detected by the buckle connectiondetector 16. If attaching of the seatbelt tongue to the buckle has beendetected, the present processing is immediately terminated, whereas ifattaching of the seatbelt tongue to the buckle has not been detected, itis determined at a step S4302 whether the seatbelt is being protracted,from the terminal voltage across the DC motor 10. If the seatbelt is notbeing protracted, the same determination is repeated, whereas if theseatbelt is being protracted, the terminal voltage across the DC motor10 is measured at a step S4303. More specifically, an amount ofprotraction of the seatbelt over a predetermined time period (e.g. 0.5sec) is calculated from the measured terminal voltage.

[0379] An example of the manner of calculating the amount of protractionof the seatbelt, i.e. a length of the seatbelt protracted will bedescribed hereinbelow.

[0380]FIG. 43 is a block diagram showing contents of arithmeticprocessing executed by the MPU 14 according to the present embodimentprovided in the electric retractor 1100.

[0381] The MPU 14 is comprised of a digital filtering block (high-passfilter) 84 for extracting only pulsating components from voltage signalsfrom the IFs IF3 and IF4, a counting block 85 for counting a number oftimes the extracted pulsating components rise a predetermined voltage v0(e.g. 1 volt) from a level below the predetermined voltage, aprotraction/retraction amount calculating block 86 for calculating anamount of protraction or retraction of the seatbelt, based upon a countvalue obtained by the counting block 85, a digital filtering block(low-pass filter) 87 for removing only pulsating components from thevoltage signals from the IFs IF3 and IF4, and a motor rotationaldirection detecting block 88 for detecting whether the rotationaldirection of the DC motor 10 is in the seatbelt protracting direction orin the seatbelt retracting direction, based upon the sign of the voltagesignals with pulsating components removed therefrom.

[0382] Next, the operation of these blocks of the electric retractor1100 for calculating the protraction amount or the retraction amount ofthe seatbelt will be described.

[0383] When the seatbelt has been protracted by the occupant, the reelshaft 3 is rotated, and the rotation is transmitted through the reelshaft pulley 5, the DC motor pulley 6, and the power transmission belt 7to the rotary shaft of the DC motor 10 to rotate the same, whereby anelectromotive force is generated. The A/D converter 83 samples theresulting voltage signals from the IFs IF3 and IF4 every predeterminedtime period.

[0384] In the digital filtering block 84, the voltage signal from the IFIF4 is subtracted from the voltage signal from the IF IF3, and theresulting difference voltage is subjected to high-pass filtering toextract only pulsating components therefrom. The counting block 85counts the number of times the extracted pulsating components rise abovethe predetermined value V0 from a level below the same, and a signalindicative of the count value is delivered to the protraction/retractionamount calculating block 86.

[0385] On the other hand, in the digital filtering block 87, the voltagesignal from the IF IF4 is subtracted from the voltage signal from the IFIF3, and the resulting difference voltage is subjected to low-passfiltering to remove only pulsating components therefrom. The resultingvoltage signal free of pulsating components is delivered to the motorrotational direction detecting block 88, which in turn detects whetherthe rotational direction of the DC motor 10 is in the seatbeltprotracting direction or in the seatbelt retracting direction, basedupon the sign of the voltage signals free of pulsating components, anddelivers a signal indicative of results of the detection (the seatbeltprotracting direction in the present case) to the protraction/retractionamount calculating block 86.

[0386] In the protraction/retraction amount calculating block 86, thecount value from the counting block 85 is multiplied by a predeterminedvalue (e.g. 10 cm/1 count), and the amount of protraction of theseatbelt is calculated based upon the resulting product and the signalindicative of the detected rotational direction of the DC motor 10 fromthe motor rotational direction detecting block 88.

[0387] Referring back to FIG. 42, after the calculation of the length ofthe seatbelt over the predetermined time period (0.5 sec) at the stepS4304, the speed v of protracting the seatbelt is calculated at a stepS4305, and based upon the calculated protracting speed v, a waiting timet1 after stoppage of protraction of the seatbelt is set at a step S4306.The waiting time t1 is set in the following manner, for example: TABLE 1PROTRACTING SPEED v (m/s) WAITING TIME t1 (s) v > 0.5 t1 = 1.5 0.5 ≧ v ≧0.3 t1 = 3 0.3 > v t1 = 5

[0388] The above setting of the waiting time t1 takes into considerationthe fact that in the case of an occupant having a high physical ability,the seatbelt protracting speed is high and the time period afterstoppage of protraction of the seatbelt by the occupant and beforecompletion of mounting of the seatbelt onto his body is relativelyshort, whereas in the case of an occupant having a low physical ability,the seatbelt protracting speed is low and the time period after theoccupant protracts and before completion of mounting of the seatbeltonto his body is relatively long.

[0389] Next, it is determined at a step S4307 whether the protraction ofthe seatbelt has been terminated, from the current i flowing to the DCmotor 10. If the protraction has not been terminated, the processingreturns to the step S4303, whereas if the protraction has beenterminated, it is determined at a step S4308 whether the waiting time t1has elapsed after the termination of protraction of the seatbelt. If thewaiting time t1 has elapsed, the seat storing control of FIG. 18 isexecuted at a step S4309, followed by terminating the presentprocessing. If the waiting time t1 has not elapsed, it is determined ata step S4310 whether attaching of the seatbelt tongue to the buckle hasbeen again detected by the buckle connection detector 16. If attachingof the seatbelt tongue has not been detected, the processing returns tothe step S4308, whereas if attaching of the seatbelt tongue has beendetected, the present processing is terminated.

[0390] As described above, according to the present embodiment, thewaiting time t1 after the stoppage of protraction of the seatbelt is setaccording to the seatbelt protracting speed. As a result, even when anoccupant of a high physical ability gets off the vehicle and closes thedoor in a short time after protracting the seatbelt, it can be preventedthat the seatbelt is caught in the door. On the other hand, when anoccupant of a low physical ability mounts the seatbelt onto his body, itcan be prevented that the seatbelt starts to be retracted before hefinishes mounting the seatbelt onto his body to impede his mountingmotion, whereby a comfortable seatbelt attaching environment isprovided.

[0391] Twelfth Embodiment

[0392] An automotive passenger restraint and protection apparatusaccording to a twelfth embodiment of the invention includes an electricretractor 1200, which is distinguished from the electric retractor 100of FIG. 1 in that a danger degree detector 89 for detecting a degree ofdanger of collision of the automotive vehicle is connected to the MPU14, in place of the temperature sensor 19 in FIG. 1. Except for this,the construction of the electric retractor 1200 is identical with thatof the electric retractor 100, description of which is thereforeomitted.

[0393]FIG. 44 shows the arrangement of the electric retractor 1200according to the present embodiment.

[0394] As shown in FIG. 44, the danger degree detector 89 is connectedto the MPU 14.

[0395] The danger degree detector 89 is comprised of a vehicle speedsensor 90 for sensing the traveling speed of the automotive vehicle, abraking detector 91 for detecting stepping-on of a brake pedal of theautomotive vehicle, a steering angle detector 92 for detecting thesteering angle of a steering arm of the vehicle, an ambient illuminancedetector 93 for detecting ambient illuminance of the vehicle, and araindrop detector 94 for sensing raindrops.

[0396]FIG. 45 is a schematic view showing the interior of the vehiclecompartment, which is applied to the present embodiment.

[0397] Fixed to an inner wall of the vehicle compartment is a supportshaft of the brake pedal which is normally biased in a non-stepped-onposition by a spring. Mounted within the support shaft of the brakepedal is an angle sensor, not shown, which rotates in unison withmovement of the brake pedal and is connected to the braking detector 91in FIG. 44.

[0398] The braking detector 91 calculates the stepping-on force from anangle sensed by the angle sensor to thereby detect stepping-on of thebrake, and calculates the stepping-on speed, from a time change in thesensed angle.

[0399] Alternatively, the braking detector 91 may detect whetherdeceleration of the automotive vehicle sensed by a G sensor or a likesensor is smaller than a predetermined value, or whether a time changein the vehicle speed sensed by the vehicle sensor 90 exceeds apredetermined degree of deceleration.

[0400] The steering angle detector 92 is connected to a potentiometerrotatable in unison with rotation of a column at the center of thesteering arm and detects the steering angle, based upon a signal fromthe potentiometer. Further, the steering angle detector 92 also detectsa rate of change in the steering angle, from a time change in thesteering angle.

[0401] The ambient illuminance detector 93 is connected to a photosensor such as a photo diode. The photo sensor is arranged between aninternal mirror of the automotive vehicle and a windshield of the same,for receiving light from the outside through the windshield. An outputsignal indicative of the sensed intensity of light from the photo sensoris delivered to the ambient illuminance detector 93, which in turndetects the ambient illuminance from the output signal.

[0402] The raindrop detector 94 is connected to two electrodes on aninsulating board arranged on a bonnet of the vehicle. The resistancebetween the two electrodes varies with the amount of raindrops, and asignal indicative of the amount of raindrops is delivered to theraindrop detector 94, which in turn detects the presence of raindropsfrom the signal.

[0403]FIG. 46 is a flowchart showing a control program according to thepresent embodiment, executed by the MPU 14.

[0404] First, it is determined at a step S4601 whether attaching of theseatbelt tongue to the buckle has been detected by the buckle connectiondetector 16. If attaching of the seatbelt tongue has not been detected,the present processing is immediately terminated, whereas if attachingof the seatbelt tongue has been detected, it is determined at a stepS4602 whether a significant degree of danger has been detected by thedanger degree detector 89. It is determined that the significant degreeof danger has been detected, if the vehicle speed detected by thevehicle speed detector 90 exceeds a predetermined value (e.g. 60 km/h)and at the same time at least one of the following conditions isdetected:

[0405] (1) Braking has been detected by the braking detector 91;

[0406] (2) The rate of change in the steering angle detected by thesteering angle detector 92 exceeds a predetermined value;

[0407] (3) The ambient illuminance detected by the ambient illuminancedetector 94 exceeds a predetermined value; and

[0408] (4) Raindrops have been detected by the raindrop detector 94.

[0409] If it is determined at the step S4602 that the significant degreeof danger has not been detected, first seatbelt slackening control,described hereinafter, is executed at a step S4603, whereas if thesignificant degree of danger has been detected, second seatbeltslackening control, described hereinafter, is executed at a step S4604,followed by terminating the present processing.

[0410] The present control program is executed every predetermined timeperiod t1 (e.g. 0.1 sec). However, when the determination as to thesignificant degree of danger at the step S4602 continuously provides thesame result, the first or second seatbelt slackening control is executedonly when the result of the first determination is obtained, but thesame control is not executed when the results of the seconddetermination et seq. are obtained.

[0411]FIG. 47 is a flowchart showing the first seatbelt slackeningcontrol according to the present embodiment.

[0412] First, a PWM signal is delivered from the MPU 14 to the DC motordriver 11 to rotatively drive the DC motor 10 in the seatbelt retractingdirection at a step S4701, and then it is determined at a step S4702whether the retraction of the seatbelt has reached its limit, fromcurrent flowing to the DC motor 10. When the retraction of the seatbelthas reached its limit, an improper looseness of the seatbelt has beencompletely removed.

[0413] If it is determined at the step S4702 that the retraction of theseatbelt has not reached its limit, the processing returns to the stepS4701, whereas if the retraction has reached the limit, a PWM signal isdelivered from the MPU 14 to the DC motor driver 11 to rotatively drivethe DC motor 10 in the seatbelt protracting direction at a step S4703,and then it is determined at a step S4704 whether a predetermined timeperiod t2 (e.g. 1 sec) has elapsed after the start of the driving of theDC motor 10 in the seatbelt protracting direction. When thepredetermined time period t2 has elapsed, a proper amount of loosenesshas been given to the seatbelt and hence to the occupant.

[0414] If it is determined at the step S4704 that the predetermined timeperiod t2 has not elapsed, the processing returns to the step S4703,whereas if the predetermined time period t2 has elapsed, the protractionof the seatbelt by the DC motor 10 is stopped at a step S4705, followedby terminating the present processing.

[0415]FIG. 48 is a flowchart showing the second seatbelt slackeningcontrol according to the present embodiment.

[0416] First, a PWM signal is delivered from the MPU 14 to the DC motordriver 11 to rotatively drive the DC motor 10 in the seatbelt retractingdirection at a step S4801. On this occasion, the MPU 14 controls therotational speed of the DC motor 10 by varying the duty factor of thePWM signal.

[0417] More specifically,

[0418] (i) If the vehicle speed detected by the vehicle speed detector90 exceeds a predetermined value (e.g. 60 km/h), the rotational speed ofthe DC motor 10 is set to a higher value as the stepping-on force or thestepping-on speed detected by the braking detector 91 is larger orhigher.

[0419] (ii) If the detected vehicle speed exceeds a predetermined value(e.g. 60 km/m) and at the same time the braking detector 91 detects thatthe vehicle has been braked, the rotational speed of the DC motor 10 isset to a higher value as the detected vehicle speed is higher.

[0420] (iii) If the detected vehicle speed exceeds a predetermined value(e.g. 60 km/h), the rotational speed of the DC motor 10 is set to ahigher value as the rate of change in the steering angle detected by thesteering angle detector 92 is larger.

[0421] (iv) If the detected vehicle speed exceeds a predetermined value(e.g. 60 km/m) and at the same time the detected rate of change in thesteering angle exceeds a predetermined value, the rotational speed ofthe DC motor 10 is set to a higher value as the detected vehicle speedis higher.

[0422] (v) If the detected vehicle speed exceeds a predetermined value(e.g. 60 km/h), the rotational speed of the DC motor 10 is set to ahigher value as the ambient illuminance detected by the ambientilluminance detector 93 is lower.

[0423] (vi) If the detected vehicle speed exceeds a predetermined value(e.g. 60 km/h) and at the same time the detected ambient illuminancedetected by the ambient illuminance detector 93 is below a predeterminedvalue, the rotational speed of the DC motor 10 is set to a higher valueas the detected vehicle speed is higher.

[0424] (vii) If the detected vehicle speed exceeds a predetermined value(e.g. 60 km/m) and at the same time the raindrop detector 94 detectsraindrops, the rotational speed of the DC motor 10 is set to a highervalue as the detected vehicle speed is higher.

[0425] Next, it is determined at a step S4802 whether the retraction ofthe seatbelt has reached its limit. When the retraction of the seatbelthas reached the limit, an improper amount of looseness has beencompletely removed.

[0426] If it is determined at the step S4802 that the retraction of theseatbelt has not reached its limit, the processing returns to the stepS4801, whereas if the retraction of the seatbelt has reached the limit,a PWM signal is delivered from the MPU 14 to the DC motor driver 11 torotatively drive the DC motor 10 in the seatbelt protracting directionat a step S4803. On this occasion as well, the MPU 14 controls therotational speed of the DC motor 10 by varying the duty factor of thePWM signal, similarly to the step S4801. Therefore, by controlling therotational speed of the DC motor 10 to a higher value according to theabove control manners (i) to (vii), the time duration of the retractionof the seatbelt at the step S4801 and the time duration of theprotraction of the seatbelt at the step S4803 become shorter, to therebyshorten the time period required to shift from an amount of loosenessgiven by the first seatbelt slackening control (hereinafter referred toas “the first amount of looseness”) to an amount of looseness given bythe second seatbelt slackening control (hereinafter referred to as “thesecond amount of looseness”).

[0427] Then, it is determined at a step S4804 whether a predeterminedtime period t3 (e.g. 0 to 1 sec) has elapsed after the start of thedriving of the DC motor 10 in the seatbelt protracting direction. Whenthe predetermined time period t3 has elapsed, a proper amount oflooseness has been given to the seatbelt and hence to the occupant. Onthis occasion, the predetermined time period t3 which is set to thetimer 15 is changed according to the degree of danger detected by thedanger degree detector 89.

[0428] More specifically,

[0429] (viii) If the vehicle speed detected by the vehicle speeddetector 90 exceeds a predetermined value (e.g. 60 km/h), thepredetermined time period t3 is set to a shorter value as thestepping-on force or the stepping-on speed detected by the brakingdetector 91 is larger or higher.

[0430] (ix) If the detected vehicle speed exceeds a predetermined value(e.g. 60 km/m) and at the same time the braking detector 91 detects thatthe vehicle has been braked, the predetermined time period t3 is set toa shorter value as the detected vehicle speed is higher.

[0431] (x) If the detected vehicle speed exceeds a predetermined value(e.g. 60 km/h), the predetermined time period t3 is set to a shortervalue as the rate of change in the steering angle detected by thesteering angle detector 92 exceeds is larger.

[0432] (xi) If the detected vehicle speed exceeds a predetermined value(e.g. 60 km/m) and at the same time the detected rate of change in thesteering angle exceeds a predetermined value, the predetermined timeperiod t3 is set to a shorter value as the detected vehicle speed ishigher.

[0433] (xii) If the detected vehicle speed exceeds a predetermined value(e.g. 60 km/h), the predetermined time period t3 is set to a shortervalue as the ambient illuminance detected by the ambient illuminancedetector 93 is lower.

[0434] (xiii) If the detected vehicle speed exceeds a predeterminedvalue (e.g. 60 km/h) and at the same time the detected ambientilluminance detected by the ambient illuminance detector 93 is below apredetermined value, the predetermined time period t3 is set to ashorter value as the detected vehicle speed is higher.

[0435] (xiv) If the detected vehicle speed exceeds a predetermined value(e.g. 60 km/m) and at the same time the raindrop detector 94 detectsraindrops, the predetermined time period t3 is set to a shorter value asthe detected vehicle speed is higher.

[0436] By shortening the predetermined time period t3 according to theabove control manners (viii) to (xiv), the time duration of driving ofthe DC motor 10 in the seatbelt protracting direction can be shorter,whereby the amount of looseness of the seatbelt can be reduced.

[0437] If it is determined at the step S4804 that the predetermined timeperiod t3 has not elapsed, the processing returns to the step S4803,whereas if the predetermined time period t3 has elapsed, the protractionof the seatbelt by the DC motor 10 is terminated at a step S4805,followed by terminating the present processing.

[0438] As described above, according to the present embodiment, when nosignificant degree of danger is detected by the danger degree detector89, that is, in a normal case, the first amount of looseness is given tothe seatbelt by executing the first seatbelt slackening control, and onthe other hand, when the significant degree of danger is detected, thesecond amount of looseness is given to the seatbelt by executing thesecond seatbelt slackening control (first amount of looseness>secondamount of looseness). As a result, a comfortable seatbelt attachingenvironment can be provided while the occupant can be properlyprotected.

[0439] Thirteenth Embodiment

[0440]FIG. 49 shows the arrangement of an automotive passenger restraintand protection apparatus according to a thirteenth embodiment of theinvention. An electric retractor provided in the present embodiment isidentical in construction with the electric retractor 100 of FIG. 1,illustration and description of which are therefore omitted.

[0441] Connected to a supply voltage input terminal of the electricretractor 100 are one of contacts 102 a of a relay 102, an emitter of atransistor 103, and an anode of a diode 101.

[0442] The other contact of the relay 102, one end of a coil 102 b ofthe relay 102, and a collector of the transistor 103 are connected to apositive terminal of a battery 105, with the other end of the coil 102 bof the relay 102 being connected to one end of a resistance 106.

[0443] The other end of the resistance 106 is connected to one end of aseating switch 104 for detecting seating of the occupant on the seat,with the other end of the seating switch 104 being grounded. The battery105 has a negative terminal thereof grounded.

[0444] The diode 101 has a cathode thereof connected to the MPU 14 aswell as to the buckle connector detector 16.

[0445] Connected to the MPU 14 are the electric retractor 100, buckleconnection detector 16, seating switch 79, and a base of the transistor103 such that the MPU 14 monitors and controls these components.

[0446] The seating switch 104 is provided in a seat of the automotivevehicle at a location below the occupant sitting on the seat (sittingportion), as shown in FIGS. 50 and 51. The seating switch 104 may bearranged at any other location such as the back portion of the seat orat both the sitting portion and the back portion.

[0447]FIG. 52 shows the construction of the seating switch 104. Theseating switch 104 is comprised of a fixed electrode 107, and adeformable electrode 108 formed of an elastic material and disposedabove the fixed electrode 107 in normally spaced relation thereto. Thedeformable electrode 108 is secured to an insulating member 109. Leadwires 110 a and 110 b are connected to the electrodes 107 and 108,respectively.

[0448] The deformable electrode 108 is arranged in the seat at alocation where the occupant sits on the seat (sitting portion). Theelectrode 108 is deformed into contact with the fixed electrode 107 dueto the weight of the occupant when the occupant sits on the seat,whereby current flows through one of the lead wires 110 a, 110 b, theelectrodes 107, 108, and the other lead wire 110 a 110 b.

[0449] The control operation of the automotive passenger restraint andprotection apparatus according to the present embodiment constructed asabove will now be described with reference to FIG. 49.

[0450] When the occupant does not sit on the seat, the seating switch104 is off, and accordingly no current flows from the battery 105 to thecoil 102 b of the relay 102, with the contacts 102 a being open, wherebyno supply voltage is delivered from the battery 105 to the electricretractor 100, MPU 14, and buckle connection detector 16.

[0451] Thereafter, when the occupant sits down on the seat, the seatingswitch 104 is turned on, and accordingly current flows from the battery105 to the coil 102 b of the relay 102 to close the contacts 102 a,whereby supply voltage is delivered from the battery 105 to the electricretractor 100, MPU 14, and buckle connection detector 16. Then, the MPUdetects voltage applied to the seating switch 104 to thereby monitor onand off states of the seating switch 104.

[0452] Subsequently, when the occupant stands up from the seat, theseating switch 104 is turned off, and accordingly supply of current fromthe battery 105 to the coil 102 a of the relay 102 is stopped, wherebythe contacts 102 aof the relay 102 are opened with a time lag of 10 ms,for example, so that the delivery of supply voltage from the battery 105to the electric retractor 100, MPU 14, and buckle connection detector 16is stopped.

[0453] Simultaneously upon the turning-off of the seating switch 104,the MPU 14 delivers a high-level signal to the base of the transistor103 to turn the same on, whereby supply voltage from the battery 105 issupplied via the transistor 103 to the electric retractor 100, MPU 14,and buckle connection detector 16.

[0454] When a predetermined time period (e.g. 1 minute) within which theretraction of the seatbelt can be completed by the electric retractor100 has elapsed after the MPU 14 delivered the high-level signal to thebase of the transistor 103, the MPU 14 delivers a low-level signal tothe base of the transistor 103 to turn the same off, whereby the supplyof the supply voltage from the battery 105 to the electric retractor100, MPU 14, and buckle connection detector 16 is stopped.

[0455] Thus, the supply of supply voltage from the battery 105 iscarried out only when the occupants is seated on the seat, to therebyprevent the battery from being wastefully consumed and deteriorated,overcoming the disadvantage with the conventional electric retractorthat supply voltage from the battery to the electric retractor iscarried out even when it is not needed. Further, since the seatbelt isretracted when the seatbelt is disconnected from the buckle, it can beprevented that the seatbelt tongue is caught in the door.

[0456] As described above, according to the present embodiment, when theoccupant sits on the seat, the seating switch 104 becomes on to closethe relay 102, whereby supply voltage from the battery 105 is suppliedto the electric retractor 100, etc., and when the occupant stands upfrom the seat, the seating switch 104 becomes off to open the relay 102,whereby the supply of supply voltage from the battery to the electricretractor, etc. is stopped. As a result, wasteful consumption anddeterioration of the battery can be prevented.

[0457] Further, simultaneously when the seating switch 104 is turnedoff, the MPU 14 causes the transistor 103 to be turned on to supply thesupply voltage from the battery 105 to the electric retractor 100, etc.,and then, after the lapse of a predetermined time period within whichthe retraction of the seatbelt by the electric retractor 100 can becompleted, the MPU 14 causes the transistor 103 to be turned off to stopthe supply of the supply voltage. As a result, retraction of theseatbelt can be carried out without fail when the seatbelt isdisconnected from the occupant, to thereby prevent the seatbelt frombeing caught in the door.

[0458] Although in the present embodiment, when a predetermined timeperiod (e.g. 1 minute) after the occupant leaves the seat, the MPU 14turns the transistor 103 off, alternatively, when the occupant stands upfrom the seat, if voltage applied to the seating switch 104 is equal toa predetermined value (e.g. 7 volts) or less, for example, the buckleconnection detector 16 may detect whether the seatbelt tongue isattached to the buckle, and if it is attached to the buckle, the MPU 14may keep the transistor 103 on for 3 minutes, while if the seatbelttongue is not attached to the buckle, the MPU 14 may keep the transistor103 on for 30 seconds.

[0459] Further, although in the present embodiment, the supply of powerto the electric retractor and stoppage of the same are carried outdepending upon on and off states of the seating switch, they may becarried out depending upon on and off states of an ignition switch ofthe engine connected to the battery, opening and closure of the door,whether the vehicle speed is equal to 0, whether the parking brake isoperated, whether the magnitude of vibration of the vehicle is below apredetermined value, whether noise volume of the vehicle engine is belowa predetermined value, whether the engine noise has a frequencydistribution other than a predetermined frequency distribution, orwhether temperature within the engine compartment of the vehicle isbelow a predetermined value.

[0460] The automotive passenger restraint and protection apparatusesaccording to the above described embodiments may be provided at any ofthe driving seat, the assistant driving seat, and the back seats.

What is claimed is:
 1. An automotive passenger restraint and protectionapparatus for an automotive vehicle, having a seatbelt, for restrainingan occupant of the automotive vehicle by the seatbelt to protect theoccupant, comprising: danger degree determining means for determining adegree of danger of collision of the automotive vehicle; dangerpredicting means for predicting a possibility of collision of theautomotive vehicle, from the degree of danger determined by said dangerdegree determining means; collision danger signal generating means forgenerating a collision danger signal when the possibility of collisionis predicted by said danger predicting means; driving means responsiveto said collision danger signal, for carrying out alternate retractionand protraction of the seatbelt; deceleration detecting means fordetecting deceleration of the automotive vehicle; and seatbelt drivingcontrol means for controlling said driving means so as to continue thealternate retraction and protraction of the seatbelt without stoppingsame after said collision danger signal ceases to be generated and untilthe deceleration of the automotive vehicle detected by said decelerationdetecting means exceeds a predetermined value.
 2. An automotivepassenger restraint and protection apparatus for an automotive vehicle,having a seatbelt, for restraining an occupant of the automotive vehicleby the seatbelt to protect the occupant, comprising: a motor forretracting and protracting the seatbelt; seatbelt attaching statedetecting means for detecting whether the seatbelt is in a stateattached to the occupant or in a state disconnected from the occupant;danger degree detecting means for detecting a significant degree ofdanger of collision of the automotive vehicle; and control means forcontrolling said motor so as to retract the seatbelt to a limit thereofand then protract the seatbelt to thereby give a predetermined amount oflooseness to the seatbelt, wherein said control means controls saidmotor so as to give a first predetermined amount of looseness to theseatbelt when the significant degree of danger is not detected by saiddanger degree detecting means while the seatbelt is detected to be insaid-state attached to the occupant, and controls said motor so as togive a second predetermined amount of looseness to the seatbelt which issmaller than said first predetermined amount of looseness when thesignificant degree of danger is detected by said danger degree detectingmeans while the seatbelt is detected to be in said state attached to theoccupant.
 3. An automotive passenger restraint and protection apparatusas claimed in claim 2, wherein said danger degree detecting meanscomprises at least one of vehicle speed detecting means for detectingtraveling speed of the automotive vehicle, braking detecting means fordetecting stepping-on of a brake pedal of the automotive vehicle,steering angle change rate detecting means for detecting a rate ofchange in a steering angle of the automotive vehicle, ambientilluminance detecting means for detecting ambient illuminance of theautomotive vehicle, and raindrop detecting means for detecting raindropson the automotive vehicle, said danger degree detecting means detectingthe significant degree of danger if said vehicle speed detecting meansdetects that the traveling speed of the automotive vehicle is higherthan a predetermined value and at the same time at least one ofconditions is satisfied that the stepping-on of the brake pedal isdetected by said braking detecting means, the steering angle change ratedetecting means detects that the rate of change of the steering angleexceeds a predetermined value, the ambient illuminance detecting meansdetects that the ambient illuminance of the automotive vehicle is belowa predetermined value, and the raindrop detecting means detects theraindrops on the automotive vehicle.
 4. An automotive passengerrestraint and protection apparatus as claimed in claim 2, wherein saiddanger degree detecting means comprises vehicle speed detecting meansfor detecting traveling speed of the automotive vehicle, and brakingdetecting means for detecting a stepping-on force of a brake pedal ofthe automotive vehicle or stepping-on speed thereof, said control meanscontrolling said motor such that rotational speed of said motor inretracting the seatbelt is higher as the stepping-on force or thestepping-on speed detected by said braking detecting means is larger,when the traveling speed of the automotive vehicle detected by saidvehicle speed detecting means is higher than a predetermined value. 5.An automotive passenger restraint and protection apparatus as claimed inclaim 2, wherein said danger degree detecting means comprises vehiclespeed detecting means for detecting traveling speed of the automotivevehicle, and braking detecting means for detecting stepping-on of abrake pedal of the automotive vehicle, said control means controllingsaid motor such that rotational speed of said motor in retracting theseatbelt is higher as the traveling speed of the automotive vehicledetected by said vehicle speed detecting means is higher, when thedetected traveling speed is higher than a predetermined value and at thesame time the stepping-on of the brake pedal is detected by said brakingdetecting means.
 6. An automotive passenger restraint and protectionapparatus as claimed in claim 2, wherein said danger degree detectingmeans comprises vehicle speed detecting means for detecting travelingspeed of the automotive vehicle, and steering angle change ratedetecting means for detecting a rate of change in a steering angle ofthe automotive vehicle, said control means controlling said motor suchthat rotational speed of said motor in retracting the seatbelt is higheras the rate of change in the steering angle detected by said steeringangle change rate detecting means is larger, when the traveling speed ofthe automotive vehicle detected by said vehicle speed detecting means ishigher than a predetermined value.
 7. An automotive passenger restraintand protection apparatus as claimed in claim 2, wherein said dangerdegree detecting means comprises vehicle speed detecting means fordetecting traveling speed of the automotive vehicle, and steering anglechange rate detecting means for detecting a rate of change in a steeringangle of the automotive vehicle, said control means controlling saidmotor such that rotational speed of said motor in retracting theseatbelt is higher as the traveling speed of the automotive vehicledetected by said vehicle speed detecting means is higher, when thedetected traveling speed is higher than a predetermined value and at thesame time the rate of change in the steering angle detected by saidsteering angle change rate detecting means is larger than apredetermined value.
 8. An automotive passenger restraint and protectionapparatus as claimed in claim 2, wherein said danger degree detectingmeans comprises vehicle speed detecting means for detecting travelingspeed of the automotive vehicle, and ambient illuminance detecting meansfor detecting ambient illuminance of the automotive vehicle, saidcontrol means controlling said motor such that rotational speed of saidmotor in retracting the seatbelt is higher as the ambient illuminancedetected by said ambient illuminance detecting means is smaller, whenthe traveling speed of the automotive vehicle detected by said vehiclespeed detecting means is higher than a predetermined value.
 9. Anautomotive passenger restraint and protection apparatus as claimed inclaim 2, wherein said danger degree detecting means comprises vehiclespeed detecting means for detecting traveling speed of the automotivevehicle, and ambient illuminance detecting means for detecting ambientilluminance of the automotive vehicle, said control means controllingsaid motor such that rotational speed of said motor in retracting theseatbelt is higher as the traveling speed of the automotive vehicledetected by said vehicle speed detecting means is higher, when thedetected traveling speed is higher than a predetermined value and at thesame time the ambient illuminance detected by said ambient illuminancedetecting means is smaller than a predetermined value.
 10. An automotivepassenger restraint and protection apparatus as claimed in claim 2,wherein said danger degree detecting means comprises vehicle speeddetecting means for detecting traveling speed of the automotive vehicle,and raindrop detecting means for detecting raindrop on the automotivevehicle, said control means controlling said motor such that rotationalspeed of said motor in retracting the seatbelt is higher as thetraveling speed of the automotive vehicle detected by said vehicle speeddetecting means is higher, when the detected traveling speed is higherthan a predetermined value and at the same time the raindrops aredetected by said raindrop detecting means.
 11. An automotive passengerrestraint and protection apparatus as claimed in claim 2, wherein saiddanger degree detecting means comprises vehicle speed detecting meansfor detecting traveling speed of the automotive vehicle, and brakingdetecting means for detecting a stepping-on force of a brake pedal ofthe automotive vehicle or stepping-on speed thereof, said control meanscontrolling said motor such that an amount of protraction of theseatbelt is smaller as the stepping-on force or the stepping-on speeddetected by said braking detecting means is larger, when the travelingspeed of the automotive vehicle detected by said vehicle speed detectingmeans is higher than a predetermined value.
 12. An automotive passengerrestraint and protection apparatus as claimed in claim 2, wherein saiddanger degree detecting means comprises vehicle speed detecting meansfor detecting traveling speed of the automotive vehicle, and brakingdetecting means for detecting stepping-on of a brake pedal of theautomotive vehicle, said control means controlling said motor such thatan amount of protraction of the seatbelt is smaller as the travelingspeed of the automotive vehicle detected by said vehicle speed detectingmeans is higher, when the detected traveling speed is higher than apredetermined value and at the same time the stepping-on of the brakepedal is detected by said braking detecting means.
 13. An automotivepassenger restraint and protection apparatus as claimed in claim 2,wherein said danger degree detecting means comprises vehicle speeddetecting means for detecting traveling speed of the automotive vehicle,and steering angle change rate detecting means for detecting a rate ofchange in a steering angle of the automotive vehicle, said control meanscontrolling said motor such that an amount of protraction of theseatbelt is smaller as the rate of change in the steering angle detectedby said steering angle change rate detecting means is larger, when thetraveling speed of the automotive vehicle detected by said vehicle speeddetecting means is higher than a predetermined value.
 14. An automotivepassenger restraint and protection apparatus as claimed in claim 2,wherein said danger degree detecting means comprises vehicle speeddetecting means for detecting traveling speed of the automotive vehicle,and steering angle change rate detecting means for detecting a rate ofchange in a steering angle of the automotive vehicle, said control meanscontrolling said motor such that an amount of protraction of theseatbelt is smaller as the traveling speed of the automotive vehicledetected by said vehicle speed detecting means is higher, when thedetected traveling speed is higher than a predetermined value and at thesame time the rate of change in the steering angle detected by saidsteering angle change rate detecting means is larger than apredetermined value.
 15. An automotive passenger restraint andprotection apparatus as claimed in claim 2, wherein said danger degreedetecting means comprises vehicle speed detecting means for detectingtraveling speed of the automotive vehicle, and ambient illuminancedetecting means for detecting ambient illuminance of the automotivevehicle, said control means controlling said motor such that an amountof protraction of the seatbelt is smaller as the ambient illuminancedetected by the ambient illuminance detecting means is smaller, when thetraveling speed of the automotive vehicle detected by said vehicle speeddetecting means is higher than a predetermined value.
 16. An automotivepassenger restraint and protection apparatus as claimed in claim 2,wherein said danger degree detecting means comprises vehicle speeddetecting means for detecting traveling speed of the automotive vehicle,and ambient illuminance detecting means for detecting ambientilluminance of the automotive vehicle, said control means controllingsaid motor such that an amount of protraction of the seatbelt is smalleras the traveling speed of the automotive vehicle detected by saidvehicle speed detecting means is higher, when the detected travelingspeed is higher than a predetermined value and at the same time theambient illuminance detected by the ambient illuminance detecting meansis smaller than a predetermined value.
 17. An automotive passengerrestraint and protection apparatus as claimed in claim 2, wherein saiddanger degree detecting means comprises vehicle speed detecting meansfor detecting traveling speed of the automotive vehicle, and raindropdetecting means for detecting raindrops on the automotive vehicle, saidcontrol means controlling said motor such that an amount of protractionof the seatbelt is smaller as the traveling speed of the automotivevehicle detected by said vehicle speed detecting means is higher, whenthe detected traveling speed is higher than a predetermined value and atthe same time the raindrops are detected by said raindrop detectingmeans.